No, it is not comparable. Not at all.

Apart from the blatant qualitative difference, you can't dismiss the context of the holocaust. The intent of displacement and genocide matters, it's not the marking of people per se.

If you can't help yourself and absolutely must use a Nazi reference, a DNS block list is closer related to a book burning, than the planned, industrialized murder of millions of people. But really, censorship isn't the defining characteristic of the Nazi terror, so unless you explicitly want to invoke the topic of ethnic cleansing, I strongly suggest you look elsewhere.