I am not a lawyer, but I don't think it is illegal for Facebook to censor and deny service to anyone they want. (Somebody can correct me if I am wrong). And in similar fashion, everybody is perfectly free to use Facebook and comply with their rules, or choose not to use it.
Maybe it is me, but I am having really difficult time understanding why people take Facebook so seriously and add so much value to it. It is just another cheap entertainment website. There are so many more.