I'd go further: the only people that complain about gatekeeping are the people it's good to keep out.

There's almost always no other barrier than "liking the thing and participating", and even if a community wants to keep out certain types of people, you can just make your own community to enjoy it with like-minded individuals. Otherwise, it's just selfish "grass is greener" and "I want what you have because you have it and I don't" thinking.