This is a complete fallacy.
Starting with Robert receiving far less backlash than, say, Ben Afleck, and his haters at this point are mostly certain cultists.
Robert was one of the top fancast for the fanboys, and any detractor was getting educated with his filmography, there was a lot of support for him. Let's not forget.
If you can't see the big difference between of criticism about Robert and the criticism about Kristen in this very forum (I don't even have to send you somewhere else), there's nothing I can do.
To them, Robert was suddenly the greatest actor of all time and they were always bringing his movies up, but for the "same people" apparently Kristen's filmography was literal non-existent, and you can see it in the respective Spencer thread, there was nothing that could make them change their minds (ironically same people who now stan for RP).