Also, there’s the principle that once you put something on a web site and make it available to everyone you’re literally gifting it to them. It’s not like they had no right to it. You invited that.
Now, republishing your material on another site, that’s where it gets sticky. It’s not like people are free to take everything you put on a site and reproduce it on their own. That’s where it starts becoming theft (depending on the circumstances).
Do they honor requests to remove sites from their database?