CBS doesn't have to accept just any/all advertising.
They won't accept "Where's the Birth Certificate" advertising.
Political reasons for that. And I don't hear the "progressives", nor the gays, saying that it's "discrimination" or "censorship" in that case.
Common sense also tells the reasonable person that Super Bowl fans don't want to see same-sex make-out scenes and would tend to boycott the Super Bowl in the future if that happened. Doesn't matter if it's two girls or two guys- sorry, but Mainstream Americana just doesn't want to have that imposed upon them, and will retaliate by walking away and taking their pocket money elsewhere. Sure, let the "progressives", the gays and the Big Old Media call such a response "hateful" or whatever, but, hey, guess what? Being "hateful" is NOT a crime. It's a human right. After all, if it's ok for gays, "progressives" and the Big Old Media to be "hateful" and get away with it, then it must therefore be a human right, right? No double standards shall be allowed, in the name of equality and fairness! Let people boycott whatever promotes, deliberately or not, things that people don't want to see, don't want to hear about.
In fact, believe it or not, most folks don't even want to see anybody making out, whether homo, hetero or some other preference. Why do you think that millions of people stopped watching movies following the liberalization of Hollywood productions in the 1960s (I cite "Media Revolution" for that information)? They don't want to see that stuff in public, even if it's only via two-dimensional images. Such stuff offends a LOT of people. Why dare impose it, if it might offend someone? Why is it bad to offend gay folks, but not regular folks? Why the double standard? Are regular folks second-class relative to the first-class gay folks? Ok to impose extremist stuff on regular folks, but regular folks are expected to kiss gayfolk ass all the time?
Look, we reasonable folks don't have a problem with girls who like to make our with girls, nor with men who like to make out with men. We really don't care, so long as they do it in private, and keep it out of public (like the ACLU wants to push Christianity evidence out of the public and into the private, all the time). We don't want it to be evident in public, pushed at us via a big screen when we're trying to enjoy non-ideological stuff.
We should start declaring that there's a "Constitutional principle" of "separation of sexuality and state" and use this big lie to keep commercials with people making out in them from being broadcast, as it violates the principle of sexuality and state. Yep, it's time to strike back at the dangerously-hateful-bigot JudeoChristianophobes by giving them a taste of their own medicine. Yeah! C'mon- if it's ok for them to do it to us, then it's ok for us to do the same. Of course, they'll say that if we do it, too, then we've "got no 'integrity'". As if they've got "integrity" up the yin-yang (sometimes impossible, because they sometimes have something else up there!).
Yes, people can just walk out of the Super Bowl and stay away. But then what??? Would that be the end of the Super Bowl? Would political correctness have killed the Super Bowl? Do the folks who put it on to make money want to let political correctness fascism determine the future of their business?
Look what's happened to the Big Old Media. Always pushing stuff at the People which offends them and which the People know to be nothing but lies and manipulation, plus they're sick and tired of having important information withheld and covered up by the Big Old Media. This is why they've been, and continue to be, leaving that juggernaut for the internet, FOX News, Rush Limbaugh, etc., etc... Because they're exercising their rights and using their brains.
If CBS were to accept advertising that would hurt business by offending a lot of its clients, then CBS has a right to refuse to accept it. It's the same as if they rejected a KKK ad, or an Al Qaeda recruiting ad or a Hamas let's-hate-Israel propaganda ad. You know people would be so offended to walk out, and many would... right there and then!