They're not making shallow criticisms, they're pointing out that irony is a weak form of self-expression, which if anything takes more intelligence and honesty to realize than just saying, "It's ironic, leave it alone."

Honestly, I'm reminded of a song that's on "Fantastic Damage" by El-P. He tries to make fun of the lame misogyny that's so present in rap songs by making an over-the-top misogynistic song. I always have a private chuckle whenever I hear it because I think of how these guys, in trying to say that woman-hating is lame, can't do anything except hate women so much that it becomes ridiculous. They're incapable of making a song that is legitimately pro-woman and positive because they're still so trapped in the same mindset that they can't really think around it.

So that's the point -- irony and sarcasm are a weak person's tool of self-expression. If Sarah Silverman has nuanced and complicated ideas about race and race relations in the United States, the challenge is to make jokes about it without just repeating the same tired stuff. Instead, she just saysthe same tired stuff, only this time she adds, "But I'm doing it ironically to expose its failures!" Which isn't doing enough in the eyes of the people making critiques.