Everyone is so concerned over women and children being raped and rightfully so. Some of these transexuals look like natural born women and are hot! Anyone ever consider that they could be raped if they must go to the men's room? What makes a woman or child more important than a trans? All men (and women and children) are created equal. That's always the guiding principle when talking about discrimination.
Discrimination isn't even happening here, and even if it were it's not against the law to discriminate it is only against the law to discriminate in voting and employment. It's also against the law for states to draft laws that cause discrimination, but other than that the US Constitution lets you do as much discriminating as you want.
I don't think your preferences being offended equates to discrimination in any case. You aren't discriminated against because you don't have the job you want, for example, unless you can prove that it was age, sex, race, etc... This is just not the same case, and people are weaseling the meaning of the word to fit their agenda because they're probably under-educated.