That wasn’t the case before the ‘New Hollywood’ era of the late 1960s. Since then most conservatives have either left the film industry or make total schlock (Death Wish, Red Dawn).
Well to be honest, America itself was much more conservative in those days. They didn’t have abortion or gays at that time at all (country as a whole). Now it is a total cesspool (America itself). I can’t even imagine what it will be like in 20 years morality wise. Technology wise it is going to be awesome.