Those who are merit sources distribute merit more in the boards where they are more active and post, but they do not distribute merit in the boards where they do not post because they are not interested in those topics. However, since there are different boards in this forum and it is created from the forum, of course merit distribution is necessary for good posts in each board. But these topics are not seen in places like Economics, Trading Discussion, Altcoin Discussion, Trading Discussion, Politics. It is not that merit is not given in these, but it is given in a much smaller amount. So, of course, you should keep an eye on these boards. Although I myself do not post on politics because I am not interested in political debates, there are some posts here that deserve merit.
I agree with you that there are some good posts that are merit worthy. However, as you said, if the merit sources does not visit those threads, they won't be able to see those posts. I assume majority of the merit sources do not like political discussions as well, which is why they do not read those posts. As a result, there are less merit distributions in those boards. The good thing is, there are some threads where you can report good posts to be merited.
If you thing there are some posts/topics that deserve merit, you can always collect the link and post in those threads to get them merited. I actually don't care much about merits anymore, which is why I do not report either.