You ask, What makes it worth defending? and the only answer I can give is this: Freedom to write, freedom to read, freedom to own material that you believe is worth defending means you’re going to have to stand up for stuff you don’t believe is worth defending, even stuff you find actively distasteful, because laws are big blunt instruments that do not differentiate between what you like and what you don’t, because prosecutors are humans and bear grudges and fight for re-election, because one person’s obscenity is another person’s art.