No one actually believes Jim Acosta did anything wrong.
This is one of those situations where conservatives collectively pretend to believe something they don’t believe.
Pretending to believe something they don’t believe serves multiple purposes.
One, it signals tribal loyalty. Being willing to say blatantly false things shows you put tribe over truth, and that is a critical loyalty test, as anyone who has studied cults can tell you.
Two, they’re trolling. “Triggering the libs” is the meats and potatoes of their political ideology these days (read my book, Troll Nation). Telling blatant lies and watching liberals make themselves crazy insisting on “facts” and “evidence” makes them laugh in delight.