I'm not sure that anyone but some real nutjobs truly hated the guy, but he was really stupid when dealing with his situation. I'm not even talking about the dreaded 3 tweets he made, I'm talking about the couple of months before that when his decision making completely failed him.
In giving him the benefit of the doubt solely because his side is the only one we have, he explained in his 'return' video that his music had been stolen by some fags and given to a distributer to put onto spotify, youtube music, and other music platforms which in-turn could be used to strike his own channel into deletion. So he contacted that distributor, cleared up the situation, and the distributor terminated the rights of that entity from distributing music through them. He claims it happened more than once and so to stop it from happening again he made his first and most retarded decision. He decided to flaunt copyright law and put his music onto platforms such as spotify, apple music, bandcamp, etc., via a distributor, which means he is legally claiming ownership of the content therein and that he has received expressed permission to use copyrighted content contained within his work. He did this because he said he was afraid one of the bad actors out there would eventually end up blowing up his channel or striking the holo streams that used his stuff.
Of course, cover struck the spotify stuff, but curiously, didn't hit all of his songs with Hololive copyrighted material in them, and also they didn't hit any other monetary music streaming service other than spotify. I can only assume Holo Bass is still making money from those platforms, but regardless he was confused as to the criteria he needed to meet to be struck. After not getting a response from Cover he claims that he was going to drop it, but then Cover released their derivative works guidelines, which Holo Bass had questions about and wanted clarification on some of the statements made in the document. So he emailed them, had his email personally handed off to someone in the company, and even tried to message one of the talents, trying to get into contact with someone that could answer his questions. Obviously these efforts failed and he had to just accept he might be out of luck
But wait! Amelia claimed on stream that she might have to ask for permissions to do a live performance of pop on rocks. This in turn gave Holo Bass the opening he would need to finally get his questions answered! In reality, no one ever contacted him, I assume because they realized they didn't really need his permission, but when Ame sang the song anyway, his frustration boiled over and he made his second stupid decision of sending out the infamous 3 tweets. In regards to those, it's clear that his anger isn't because no one asked his permission, but that he hadn't been able to get into contact with anyone at Cover concerning his music. However, even slightly implying that you could conceivably strike a charity stream, even if he claims it was more about trying to demonstrate that they only respond to legal threats, is a pretty bad faith action to take.
In my opinion, Cover can be blamed for one thing, and it's that they ignored what I consider to be a reasonable set of questions pertaining to their updated guidelines. I have not seen the emails in question, but surely he would have put his questions and concerns in the emails right? However, Holo Bass intentionally ignored basic copyright law by sending his music to a distributor which would end up with him making money from copyrighted material, and then made a completely retarded set a tweets in a fuming baby-rage because he couldn't get answers from a JAPANESE COMPANY which are known for being highly autistic when it comes to dealing with consumers.