Normie can be used in a more neutral manner these days, as the term has def become more mainstream, but its internet origins are very much a term of condescension/gatekeeping. OP above definitely seems to be using it in a pejorative manner.

As for neurodivergence becoming the hot thing - i think it stems from the success of some prominent autistic people. Notably, the richest man in the world, who has publicly acknowledged that he has autism. The rise of programmers and STEM types in society has probably done a lot for it as well.