First off, you're doing what no one should ever do which is assume you know how someone you don't know is thinking or what their motivation is. Now if you happen to be cool with Matt Damon and can give us all some insight that's different but until then, you're just throwing stuff at a wall to see what works.
Secondly, I can't tell you specific actors who spoke out against Reagan but I know John Carpenter did and even made a movie about his feelings toward Reagan and his brand of conservatism in general but I haven't done a deep dive into who said what about him then and the same goes for Bush when it comes to the simpsons calling him out but again, I haven't done a deep dive so that's off the top of my head.
Now as far as Clinton goes, I've done research on that because of a class I took and you're right, comedians got at him, other politicians got at him (including liberals) and the west wing is a direct response to him, not for his thing with Monica, but just for his brand of liberalism which was triangulation and being a centrist. BUT, I'd argue that him doing what he did with Monica is in no way shape or form equal to what the NSA did. Not even close and I'm a hardcore liberal who's campaigned for Obama, campaigned for his surrogates, and voted for the man twice and would do it a 3rd time. But I can still have issues with things the man has done and there's nothing wrong with Damon, you, me, or any other celebrity who voted for the man, campaigned for the man, and donated handsomely to his campaign to speak up about it.
If you want to say that's because he's black, cool, that's how you feel but I'm not going to pretend to know what someone I never met is thinking, especially when I understand exactly where he's coming from