Movies too dated to be enjoyable

What do you think of the opinion that movies made before WW2 are too dated? My parents really don’t like them, and they actually grew up in the '40s. So how did you come by your liking for them? Is it anything similar to what salinqmind mentions?

I have a few…early WWII movies-especially those starring Errol Flynn (a draft dodger). Most ofthe “oriental detective” movies (“Carley Chan”, “Mr. Moto”, etc.).
Those 1950’s monster movies (like “The Blob”).
I agree that “2001” was incredibly long and boring.