It's probably because of how ridiculous some of the people bashing him online tend to get.
I generally consider myself relatively neutral in that particular fight, and I still kind of chuckle at how stupid some of the more vocal whiners tend to get about literally everything he does, to the point where they just come across more like petty assholes and childish crybabies than they do the valiant crusaders against injustice and corruption they like to see themselves as.
The really funny part is, all the complaining about minor things and constant insults/abuse has effectively created a "sky is falling"/"boy who cried wolf" sort of situation, where even when major things DO occur, or stuff Trump probably SHOULD be criticized for happens, a lot of people completely ignore it because they've spent the last few years being conditioned to tune out criticism. A lot of otherwise neutral or centrist people no longer give a single shit because they just assume the anti-Trump fanatics are blowing everything out of proportion (as usual). The people who hate him the most and can't stop ranting about him may be his most effective supporters.
Those people should be using their own fucking brain to figure out how bad he is instead of just thinking like the hive mind of his fans and others that think he is okay at least "Oh man those dumb liberals keep blowing this shit out of proportion, Trump is doing a good or okay job at least!"
Only in this country in today's world could someone do such a piss poor job that people think it's all fake news and/or whiners.