First, I am not saying their comfort supercedes anyone else's, or even that it is a legitimate area for the law to consider.
Second, it's beyond debate that transgenderism is a mental issue. Go pick up any book on it and it's either written by a psychiatrist or it's someone's tale of how they were treated by a psychiatrist for years. Some group of idiots (a minority even in the transsexual community) saying it's not changes nothing.
Are you saying that a majority of the transsexual “community” believe they have mental issues? I honestly have never heard anyone who identified as a member of that “community” suggest that.