I think if a post is deleted for whatever reason then people should lose that merit as well. I think some people are purposely deleting their merited posts after they've received merit for it for whatever reason. Anyone can just merit some random trash post then delete it to get rid of the evidence. People could also just copy content then deleted the post once it's been merited. It's ripe for abuse if the merit stays after the post has gone.
Yeah thats a good point, its perfect for noobs to create multiple accounts & give themselves Merit points for shit posts they then delete which somewhat removes part of the trace. Its much more difficult to prove Merit abuse if the post is deleted.