Yours is the first comment I've seen on that track, and that was my initial thought. The recreation center may have a non-discrimination policy, but any martial arts instructor must discriminate, or subsequently could be held liable for the mis-use of what he/she teaches.
One solution would be to teach completely separate classes, by skill level, at the approval of the instructor(s).
Personally, I would never (these days) teach anything above beginner level techniques to a muslim, or a communist, on an inner-city yute, or any other person of questionable character -- and the only way to determine their character is to observe their behavior in the beginning classes and their interactions with other beginning students.
Many Japanese martial arts schools have done this to American students since the USA dropped the boomers on a couple of their cities. American students in Karate classes generally get ten or fifteen years of horribly disfiguring calisthenics, with very little useful martial arts skills beyond the horribly taught poor forms of basic punches, blocks, and kicks (along with a whole lot of totally useless Japanese yells for "soy sauce" and "saki").
A good instructor would save the aikido (or hapkido) skills for the "advanced" classes, and have the muslim new-comers square off against a concrete wall for ten or fifteen years of straight-toe kicks, finger spears, head-butts, etc.
I wouldn’t teach a muzzie how to shoot a rubber band gun. ;-)