We do not have the authority to enforce rules all over. But ddf being a private and closed community, can formulate its own set of rules. and we have clearly mentioned the restrictions on the terms, privacy policy and the forum rules. It's not necessary for anyone who doesn't agree to it to register on the site. It is clearly mentioned not to use the site if you don't agree to it. You have agreed to it accepted to follow it in order to use the site. Now talking otherwise.
And please do understand about freedom of speech. The freedom of speech gives you freedom to speak and prevents the govt. to curb your freedom. I can't go out to the street and start abusing my neighbour saying i have freedom of speech. He would just kick me on the face. No questions asked.
A forum or any website for that matter is a private property and can impose restrictions about how THEIR OWN SITE works. We aren't misusing the power, but don't misuse your fundamental rights.