"The sources, who spent time with Trump, said he was particularly incensed with the effort thus far by his attorney Bruce Castor. Trump believes Castor gave a rambling opening argument, they said. Castor’s 45-minute opening remarks were widely panned on social media after he praised the House impeachment managers for a job "well done."
"The American people just spoke and they just changed administrations," Castor said at one point. He said the public is smart enough to "pick a new administration if they don’t like the old one, and they just did."
I agree he has probably been a net negative and you're right that he gives unnecessary ammo. I do think Rudy is one of the few who has not stabbed Trump in the back though and I do think Rudy genuinely wants to support Trump. He's just been a little reckless and ineffective in that effort unfortunately.