I think its just a few loud ones that people seem to give too much attention to because the fanbase is so small and people haven't learned to ignore McGloin. The rest are just some guys memeing because a lot of people started comparing Carol and Rich when it was announced that he was going to be in the MCU.
You had people going "Well what is he going to bring to the table that Carol hasn't brought?/ We don't need Nova when we have Captain Marvel" and on the other side you had people going "They should have had Nova instead of Carol!/She stole his spotlight" Which are both dumb because they are both two completely different characters with similar powersets and they never considered Rich for the stuff Carol was in. Hell I am sure Feige took his sweet time with him the same way he took it with Carol (remember that Whedon wanted her for Avengers and Feige said no because he wanted to give Carol her own movie).
Two Richfags that I know were actually pretty excited when they saw Carol in Endgame because her going through all those Chitauri ships was cool and it also meant that they had the tech to do cool shit with Rich. When the rumors of him being in her movie were announced, Carolfags on twitter took interest in him because I tweeted a few things about him and I had a few likes from people with Carol icons.Honestly having Carol and Rich be friends in the MCU and in the comics would be a good way to stick it to those whiners.>imagine alienating part of a fanbase (which is already small enough) simply because you personally hate things so vehemently and ruin people's impression about a character you like by association.
McGloin is treated like Voldemort in the FB Nova community and they hate him for that reason.