I'm new to this forum and I'm a bit confused about the forum rule number eighteen (18), I've seen some forum users get in trouble and some get negative credit for having multiple accounts on the forum, but it clearly says it's allowed.
I am unsure why you quoted that post from 2014, as it was not related to rule 18...
In any case, to answer you... This is the rule... and it's pretty self-explanatory...:
18. Having multiple accounts and account sales are allowed, but account sales are discouraged.
So the possession of multiple is allowed, as you see... There should be no issue with having more than one account. However, those which got in trouble were users which used their alts for shenanigans, such as for cheating signature campaigns; for breaking financial deals; or other similar activities. So if you want to use a secondary account and use it in a legit way, you will not have any problems.