>Youtube does not age restrict many videos, it's seriously hard finding one that's neither gore nor porn and still age restricted.
I was going to post a link to a song based on the "All your base are belong to us" meme on another site, but it was, for some unknown reason, age-restricted.
Random videos about unionization and US foreign policy have found themselves age restricted. I won't dig them all up, but here's one which was made age restricted without appeal. Does it seem like 18+ content to you?