I don't mean that they're equivalent, I mean that they're ways to avoid labelling yourself as an atheist when you're irreligious. They're like diet atheism. Something you can say to not feel completely alienated from religious culture.

I've often said that being "agnostic" isn't a position on whether or not one believes in God. You can be agnostic theist, or agnostic atheist. But I no longer think that's accurate.

One reason people opt for it, which I find understandable, is owing to the popular connotations that atheism carries, not unlike theism. You can avoid having to explain "I'm not saying I know that God doesn't exist". But the qualifier is explicit. One needn't necessarily be certain whether they believe in a God or not and I don't think that's well represented by the term "atheist". By the same token I don't think Deism is anywhere near atheism-lite. It is explicit belief in a God with the caveat that it's irreligious.

I like the term "apatheism" because it also captures the way I feel about the question of whether God exists.