I don't have a problem with projects as long as they aren't NSFW or overly graphically violent (which would be quite hard to achieve in Scratch anyway). If you convert your project to HTML and upload it to itch like that, you can get away with a bit more than if you keep it on the actual Scratch site. It's gonna be hard for people to vote on your game if it gets taken down by an overzealous administrator. Personally I think if it's OK for someone 12-15 to play you're probably alright by me.