I really can't follow you. I spent a few minutes googling and it looks like 1) Twitter punishes 'dehumanizing tweets' 2) One author on kotaku argued that the NPC meme could be considered 'dehumanizing' 3 ???

The ban on 'dehumanization' was in response to NPC memes. It was introduced in mid October 2018 after the NPC memes became popular. They banned over 1500 accounts -- for a while they were banning every account with a NPC face in the avatar. Recall that the NPC meme originates from the (joke) that some people are robotic in their thinking, and the NPC memes are faces running a program. As this was not a violation of any twitter rules, twitter made up a rule as an excuse to block these memes.

But if you think about it, the NPC memes were not arguing that some specific individual was not human, but rather than certain types of reasoning was robotic -- e.g. atavistic, primitive, and automatic. So this was an idea that was being blocked.

Going back to religion, the whole point of religious arguments is that they offend people and challenge the core of their identity. So of course this is going to be used as a weapon against religious views. Especially if your religion includes beliefs that some people are followers of false prophets, children of the devil, etc. Religion is used in many ways as a dividing line over who is favored and who is not.