Chevy Chase in an interview likewise said that his mockery of Gerald Ford on SNL was a deliberate attempt to demean and damage a president he didn't like.

This is certainly true for Tina Fey in her burning hatred of Sarah Palin as well, if you've ever seen her interviewed on the subject.

And no doubt many other liberal actors, less prone to revealing their motives.
For many actors and comedians, their zeal for the Left and their hatred for the right (much like Pro's) is never in question.