Virtually any work of creative art can be interpreted to advocate any political or moral viewpoint. (I know, not Atlas Shrugged.)
If an author, screenwriter, composer wants their art to have any commercial or cultural relevancy, they're going to keep motivations flexible within the work. And once it's in the public forum, it's fair game for analysis.
How many were shocked to find that the creator of the supposedly ultra-libertarian Firefly launched a SuperPAC for Clinton?
How many here would never give up their love of Star Trek despite its obvious anti-capitalist, globalist (galaxist!) leanings?
I'm amazed how many times I've watched a big-budget Hollywood blockbuster and said "Hey, that has a libertarian message." At the same time, I know people with opposite inclinations confirmed their own bias with the same material quite handily.
If you try to stay away from the works of liberal artists, you're going to find entertainment in general kind of boring. Self-identifying social liberals (economics doesn't really come into it) are far more gifted in the arts than any other group.