It's fairly obvious why he does that, it's because he can't debunk the actual claims himself. He's well aware of how bad his reputation is and also doesn't want to do anything to actively change it, just complain about how he's a victim of other people. He knows that his woes are his fault but he can't and won't accept it for as long as he can.
The part that often gets forgotten is that the number of true believers is actually far lower than most recognise. Most of Phil's "fans" know he's full of shit (timbo and anonymouse both admitted to knowing that the champions thing was true while they were working for Phil and the rest only stick around for the sense of power they have) and the rest of them, namely jayde and derich, are genuine wheelchairs who don't care. They all tell Phil what he wants to read because at this point, even them telling him the truth gets to him. He lashes out when he realises they don't give him money because they think his "content" is any good. The only people safe from him in his audience are jayde and derich.
The part that makes it so much worse is that Phil is fully aware that people hate the shit he pulls. He knows that most of, if not all of his problems are completely self inflicted, it's just that his ego can't ever allow him to ever accept the blame for any of it so he has no choice but use some of the most pathetic excuses for why it's someone else's fault.
