Or people are purposefully posting in order to gain merit. If you are more likely to gain merit from creating a thread, why not create a similar thread everyday. The merit system seems broken...
I don't see it as a broken system but the adoption time will take too long as not many are aware of it. Most of the affected will be those who are here only for the bounties and have never read anything in the Meta section. Maybe they haven't even notice yet the merit points until it comes the time to rank-up.
Many "account farmers" are still spamming only for activity and many will give up at the end but if they are aware of the system on an earlier stage then we can spare some "shitposting".
Actually in thinking about it, one simple fix will actually make the merit system work. If you reduce account activity by the amount of merit NOT distributed every two weeks, it would highly encourage people to distribute merit. At the same time it might be a pain for users that have a lot to distribute but that is a separate issue.
Something like this has to be implemented for it actually to work in practice. Right now there is only incentive for abuse and power hoarding.