The U.S. Constitution:

Amendment I

Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the government for a redress of grievances.

Freedom of speech from the first amendment can be summed up this way:

Congress shall make no law abridging the freedom of speech
Within an internet forum. The webmasters of this website are not Congress. The Constitution does not say that a privately owned website must guarantee that members can say whatever they want on the forums. It simply states that CONGRESS must not abridge the freedom of speech.

Members have rights to say whatever they want, whenever they want, wherever they want: on their own property, within the confines of their own space in accordance with the laws of the land. However, members do not have freedom of speech on privately owned websites, privately owned forums.

The owner of the website/forums has the right and responsibility to create, establish, maintain rules that best fit the community and edit, ban, disable the account of any member who does not follow the website TOS. TOS (Terms of Service) or Guidelines are king.

Freedom of Speech does not apply to all citizens of the world simply because they are posting on an American owned website? Also that the Freedom of Speech they so desperately cling to is not theirs when they post on a website not owned by them?