Need a little Help with something

What i am trying to do is to build a case against what hugh amount of web sites especially role playing web site are doing which is putting a ban on any one that wants to role play under age characters.

So far what I have found is that there does not appear to no such law, as it would it appear to clearly violate the first amendment and that is exactly what all this websites are doing and I am serious considering writing congress about it as it is a clear violation of the first amendment and it may also clearly fall into the category of writers rights also.

International, regional and national standards also recognize that freedom of speech, as the freedom of expression, includes any medium, whether orally, in writing, in print, through the internet or art forms

Note I am mainly referring to text not art