If we're being genuine (i know we aren't), Sayu saw her own plight as a reason for a call to arms against Nijisanji, but she was barely around for a month, and seemed to piss off everyone not just in her wave, but "the clique", and would later be seen dredging up old drama for seemingly no reason
Compare that to Doki/Selen, who was around from the near beginning, drummed up humongous notice in games, collabs, sponsorships and even awards. She was loved by basically everyone and was terminated over the stupidest of reasons, which caused basically everyone to side with her. She lastly told everyone to bury hatchets and not bother her "old coworkers", and went right back to being a powerhouse
Sayu ignored literally all of these differences and just saw "Doki drama > Sayu drama" and equated the seemingly biased response as people hating her, when it's closer to just realize she was unknown and gone to quick