Can't that guy sue his ex teacher for kicking him out of class for being gay? It sounds kind of unconstitutional, but then again I don't know the law there's probably some sort of loophole or something.
Discrimination based on sexual orientation is legal in most states.
Get educated: the constitution applies to the federal government. The bill of rights applies to things that the federal government can and cannot do to people (er...citizens....rather, non-enemy-combatant citizens...who have money for a lawyer...).
Don't forget. The Boy Scouts of America and the Salvation Army (if I recall correctly) openly discriminate against gays.
Discrimination laws apply mainly to employers, and to public/government organizations. For example, it's generally illegal for a private business to refuse someone a job based on their race, I know of no exceptions. High school athletic teams are not allowed to refuse anyone based on race as well. In both examples, talent (or the lack thereof) are completely valid reasons to deny entry. That's why one must interview for a job, and try out for an athletic team. As 1.2 indicated, this is a private gym, they can refuse anyone they feel like for whatever reason.
It is good to see that other Bullies aren't bigoted morons. For me, I don't give a rat's ass who it is I'm rolling with, male or female, gay or straight. All rolling partners deserve the same amount of respect that you would want them to give back. Roll at whatever level is appropriate to your relative skill levels and for what you're working at, nothing more and nothing less.
The ONLY way I could possibly think of that would honestly bother me is if I rolled with someone who had one of those weird, funky ass 'grappling fetishes' and would really 'get into it', if you get my meaning. Being a married, monogamous, faithful husband, it would probably bother me equally if I rolled with a gal who had this same reaction, not just a homo- or bi-sexual male.
This is why BJJ is gay. Everybody needs to go practice SAMBO now. (What's everybody looking at?)