Not particular political views, which are a given -- just how utterly vapid he became over time.
He was one of the main problems with the later TNG films, for what it's worth. Even in First Contact, the absurd action bits of him fighting the Borg queen in a physical little battle were mentioned as something he had pushed for in general, just as he pushed for more romantic content etc for his character (that horrific Insurrection film that committed the cardinal sin of letting actors drive it) etc. The sad realization I had to face long before ST

icard was that Stewart was once a phenomenal actor, but precisely because Picard is
very much not him.
Star Trek: Picard's failures can be closely laid at his feet. He didn't want to return to the old character, the old scholarly diplomat; he wanted an adventure, something exciting, something that would shock or surprise a fan of the original. This is embarrassing, just as his acting on Picard was thoroughly discrediting. Even in Season 3, there were precious few moments where I would rate him as even passable, and he never can close to remembering his original character at all. I actually questioned if he was on the cusp of a Bruce Willis-like gradual dementia the whole time. Utterly awful that he put his failures on screen, we could have remembered him better.