How many users are explicitly choosing that? How many users are actually choosing something very different, and this is an unintended consequence of their choice, that they would otherwise be unaware of if not for this provider taking a stand?
Internet protocols were designed to be redundant and resilient, so that things still work when things break and traffic takes other paths. When people do shit like this, we get a less reliable, less functional internet. Demanding to know the exact subnet a request originated from, and returning incorrect results when that information is not given, seems to me a thoroughly hostile behavior on the part of archive.is.
Not sending anything at all doesn't solve any of this. If a message was shown explaining the situation, sure, but archive.is solution doesn't answer your question at all.