Freedom of speech protects you from the gov and some harassment by others. This is a private site. They make the rules. Most of us follow them and are happy to do so. If you aren't, you can certainly complain, some may even agree with you. Mods are just people after all, we're not all going to agree with them all the time.
You also have the right not to participate, which you are free to do if you don't like the site or how it's run.