Yes, but part of the power of a person -- if he can be called that -- like Milo is that he acknowledges implicitly that he has absolutely no self-respect. You can call him whatever you like, however you like, and it feeds directly into his bloodstream because the further and further you go down the rabbit hole of actually *voicing* just how disgusted you are by him, the more he believes it to support his own statement: that we should just freely say whatever the fuck comes to our minds, without regard for others. He has created a distasteful image for himself, and, since he has no self-respect, he can take any criticism, especially those that the left are known for, which are decidedly less barbed than his and his followers'.
That's what makes him strong, really. Any actual attempt to discredit him, or call out his behavior for what it is, makes no actual impact on him. So, Maher stands NO chance, but not because he's basically a limp noodle of a would-be leftist who actually *agrees* with a lot of his viewpoints, but because there's actually nothing to be said to change him, or make him see how his own views degrade who he is as a person. He's given up his own humanity in seeking his goal, which is a complete devaluation of what makes us more than animals to begin with. That he is a walking contradiction, as Maher says, is tangential; he builds none of his self-worth on how he identifies as a gay man, or any other social status he has. So calling him names does very little. If anything, his status continues to imbue him with more power; as a contradiction, without critical thinking, it's not detectable for what it is: armor for his sick ideologies.
None of what he is as a contradiction matters to those who can see past it to the content of his character, which is devoid of a passion for humanity. We wonder about the contradictions; how can a person feel this way? The answer is clear: he doesn't value himself at all, he only values his bizarre message, and is willing to throw everything and everyone else under a bus to legitimize it. The way in which he uses his sexuality to claim an above-it-all status is particularly terrifying; I don't believe in God, but evil is very real, and I think it's partially embodied here.
That Maher can actually get along with the guy is deserving of ridicule, but I'd imagine that'd come mostly from people who haven't seen Maher in action before.