I, too, can separate performers from their performances.
Ed Asner is a good actor.
The character of "Lou Grant" as portrayed in the series of the same name was an irritatingly self-righteous know-it-all.
I assume that Asner used his "star power" to influence the scripts and direction to allow him to ham it up and promote his liberal causes.
Regards,
I'm afraid you nailed it.
Unfortunately that is not true. If you watch and support the show you are supporting the actor and by default his beliefs. As long as you do not hurt the person where it counts the most, in the wallet, they will not be motivated to change.