It is safe to assume that a number of proposed ads get rejected for various reasons, however, the nature of this one gets attention. I am aware of another such example where a network rejected an ad for a dating site to be aired during a sporting event. It was not a gay dating site as in this case, but was rejected just the same. If an ad for a heterosexual dating site can be rejected by a network, why can't one that markets toward homosexuals? From what I gather, there is little difficulty in selling ad time for the Superbowl, and as such, I'm sure the network can be selective in the ads they choose to air. Rather than a decision derived from perceived prejudice, it could be a simple business decision. Either way, a network has that entitlement, even though it may not be in agreement with everyone.
It seems fashionable nowadays to affix labels to anyone who may not be in agreement with "modern" lifestyles or behaviors. If one does not agree with homosexuality, they are immediately labeled as being homophobic, even if they do nothing discriminatory against that group of people. I find that offensive. The current sentiment seems to be that you must be willing to not only be tolerant of, but also promote such a lifestyle or be branded a bigot. Nowhere is it written that gays have to be afforded the right to advertise dating sites for casual sex on television networks. The same is true of a dating site of any persuasion. We all have different views on what we find acceptable and will at times express vastly different values. Networks are run by people, just like us, who have their own views and ideologies. It would be near impossible to make decisions that would appease everyone in society. In the end, television is an industry based heavily on image and marketing. If such an ad does not correspond with the image the network wants to project, so be it.