Put it this way: if, say, CD Projekt Red had purchased Psyonix, this reaction would not have occurred.
Because you need two things to judge an action. The act itself and the motivation behind it.
Microsoft recently bought many studios and the community was rather positive about it.
Now ask yourself, why do you think epic bought psyonix? Because psyonix pitched a great idea to epic and epic saw so much value in the studio that they decided to support and invest into them? Because they want psyonix to take over one of epic's IPs?
Or because epic just wants to damage steam and have one more, aggressive lever to force costumers to come to them.