Apart from what you have mentioned, this thread became heaven for the merit farmers and abusers. Whether they do the pushups or not, they report regularly to get some merits, and some forum members never disappoint them. I have been checking some profiles lately and noticed they use some threads to farm merits, and this thread is one of them. Another one is the Buy Dip Hold thread, which they use.
I also noticed the same thing too that some users farm merits in most of this threads and take advantage of the merit sources active in those threads but then I observed that they don’t just issue out merits without reading a post and they don’t merit low quality posts or spammers so they still have make good posts even though they just keep repeating themselves over and over again although there are some informative posts in the thread “Buy the Dip and Hodl”.
As for 100 push up challenge i don’t think those farming merits actually keep up with the pushups they are clearly after the merits. Only a few people on that thread will be consistent with the push ups. If they can keep up I don’t see anything wrong in the challenge, it’s actually a good way to be healthy and keep fit.