Yes, you can merit yourself but you would need two accounts for it. A lot people do this on the platform and they get away with it. People own multiple accounts and once they get merited on one account, they send that merit to their other account. This is very unfair because it denies other people who actually deserve the merits.
It would be very helpful if measures were taken to prevent self meriting as I just explained.
If you can read what the OP is referring to, you will see that is completely different from what you are saying, the OP is not saying having multiple and sending merit to each other, what he is saying is that having just one account and after creating thread or comments, then you trying to merit yourself, not sending merit from another account.
I think trading of merits from different accounts is not allowed on the forum here. Having multiple accounts is allowed but you shouldn’t cheat with those accounts, if you are sending merits to each other, then you are already cheating.