In the case of I know what I know and people don't know what I know is very wrong, everyone has different knowledge and different skills, what others might know you that thinks you know all doesn't know it, hope you guys understand what am trying to saying? Sometimes people who thinks that they can't create a quality post doesn't know that their post might be of good help to another person.
I believe that the merit system is designed to grow anyone who has a quality post that deserves it, i haven't been here for long but this is what I understand about these merit system.
I believe that I largely understand what you are trying to say, which is that each person has differing levels of personal knowledge, and sometimes they may or may not communicate their knowledge very well.
Their experiences may well still be valid, and they also might know things that other forum members do not know, but they still may need to work on improving how they communicate their ideas, whether they receive merits for improving their post quality or not.
I will also add that there are likely a decent number of forum members who probably should spend more time in terms of constructing their posts better to try to make sure that they are either communicating decently good ideas or making some kind of a point that adds value to the conversation, and surely I doubt that there is any kind of necessity that every member understands what they are saying, and in fact if they are communicating sufficiently well, then maybe only a few members will understand what they are saying, and whether they have reached a sufficient enough of a threshold of members understanding them, is not even any kind of a forum requirement, but surely, the more that they can get their posts to resonate with other forum members, then the more likely that someone will end up sending them some smerits.
Surely native speakers of English do have advantages to communicate more clearly and probably do not necessarily need to spend as much time on typing and rereading their posts, and not all new members want to earn merits, but if they do want to earn merits, then it will probably serve them better to either make sure that they are making some kind of a decently new point (and sure it could just be adding something in regards to their experiences on the topic), or that they try to write their post well and perhaps read through it a few times, try to lessen the number of errors and try to make sure that the ideas flow or are grouped in a way that makes sense.
Members do not need to be perfect, as long as they are attempting to be genuine and really attempting to add value (even if they might throw some jokes in there or some provocative statements), but if it seems like they are not really trying or they are being disingenuine, then they are likely to neither receive smerits and also some forum members might start to dislike them or even tag their account with neutral or red trust.
And, sure sometimes style can be helpful too.. so for example, if you are using the same phrases and references, then other members might start to get annoyed by your way of writing or they might lose track of what you are saying... and by the way, you do not necessarily need to be a non-native speaker or a newbie member in order for some members to detect some repetitive patterns in your style of writing and even to make fun of your way of writing. I have had members imitate my posting style, and surely, I can notice that it looks like something that I would write, and I can recognize why some of them might get annoyed with my writing style. .. but sometimes if any of us are able to practice some variety in the ways that we say things, then that can be helpful to better communicate some of our ideas a bit more clearly (and in less of an annoying way)... ..
.. even with all of this, I am not even suggesting that any member needs to give into the haters, because haters are going to hate, and you should not let the haters bother you or to direct you, unless you believe that maybe it might be the right thing to do in terms of taking some of the advice of the haters, even if you might sometimes end up taking some of their advice (based on your own choice) and perhaps without even letting the haters know that you are taking some of their mostly hater-motivated advice... and sometimes it is just funny.. sometimes haters are funny too, even if they hate you and then they tell you how much they hate you.. and not to make fun of them, but we cannot necessarily take all of these matters too seriously, even if they might have both good points and bad points all at the same time.
You explained it very well and at the same time you gave your knowledge about the different aspects of the posters. I strongly agree with you that someone's writing style really matters a lot for them to get merits because the ones who are sending merits often look for quality and information in a post. If someone tries his/her best to create good and helpful posts which can promote valid information in the best way possible then the members with such posts often receive merits every once in a while. I believe that our ultimate goal should be to serve the forum as members who could provide helpful and valuable advice to others, and not as those members who often make posts to grab merits. Well, I have seen that sometimes even if you put a lot of effort in creating a post then still you may not receive good amount of merits for such posts, but that doesn't means that you should stop producing such informative posts. At the end such posts will always be appreciated and may also gain you some merits here and there.
I agree with you that the members who are genuine and they try their best to post as much information as they have are really valuable assets to the forum. We all know that each person has different level of knowledge that he/she can share with others, but your point regarding the way of presentation is also correct. There are some members who have a lot of knowledge about the things, but sometimes they are not able to express it or present it in a way that most people can understand, and for that particular reason those members need to improve their presentation style as well as their writing style so that others can get their point without much difficulty. Those members should work on their writing style in a way that their writing readability score gets higher over time, and I also believe that using of online tools to fix grammar issues is worthless for the ones who want to improve themselves.
I'm also not a native English speaker, but I have spent a lot of hours listening to the audios of the native speakers and read many of the posts and books created by native English speakers, and that's one of the reasons which helped me to improve my English writing skills. Although, I don't really care much about my English these days but mainly focus on the way I present the knowledge that I have. I won't consider myself more knowledgeable than others, but I believe that as humans we all have different opinions and point of views regarding things, and everyone's opinion hold some kind of value in it. Finally, I would say that I agree with all the points that you have mentioned and if someone follows them with pure heart for the purpose of learning things and then sharing those things to help others then they surely will be awarded with merits for their helpful nature.