AppNexus's spokesperson Joshua Zeitz told the BBC: "We use a number of third-party standards to determine what is and isn't hate speech, and if we detect a pattern of speech that could incite violence or discrimination against a minority group, we determine that to be non-compliant and we simply won't serve ads against it. I'm not going to put the examples out there because I'm not going to engage in a tit-for-tat on what is compliant."

-----

So in other words, you don't have specific examples, you just don't like what a certain publication is saying in general so you're cutting them off.  Which is within your rights, freedom of association is a thing, but I hate being lied to about this sort of a thing.  Just say you don't like them instead of trying to diffuse the decision on anything but yourself.