if your intended audience doesn't enjoy it then you have failed, no matter how much a small subset may love it "ironically".

What if it's the reverse, that your intended audience does enjoy it, as it should, it while a large majority the total audience that enjoys is unintended? What if the intended audience is expected to love it ironically, while the unintended one adores it sincerely and earnestly, taking it at face value? Have you failed? You have achieved your win condition; the people that you thought should like it, do like it.

The humour in South Park is often, "ironically" or not, extremely immature and gross, (not to mention sharp, and original, and violent, and over-the-top, and accessible, and cruel), and thus appeals to children and teenagers. That's why that sort of humour is called juvenile. You want humour kids won't be interested in, make something like XKCD, or Discworld, or Portal, or understated stuff that requires subtlety and life experience to understand.

The same is true for porn; kids are attracted to it, once they reach puberty, even though it was not optimized for their consumption.

So what you've got to ask yourself is; "what are the sort of people who are liable to like the show, besides those for whom it is intended, and, knowing of their numbers and existence, should I make that show at all"? Why do you think Dave Chapelle cancelled the Chapelle Show? On the other hand, is there a point in not making this or that cultural product, if the "unintended audience" are going to generate something similar on their own?

• Stop distributing alcohol and people will brew at home.
• Stop distributing porn and children will masturbate to ads in Cosmo, National Geographic nudity, or even Liberty Leading The People I was raised in an Islamic country and we had no internet, and I can tell you, if worse came to worse, we used our imagination.
• Stop making ironic racist jokes on TV that a lot of people are liable to take at face value, and the same people will still make genuine racist jokes.

So, yes, there are some things that cannot be stopped. The question is; should they be encouraged, or even enabled?