Why does emet selch consider us not to be alive?

[Cleretic]

The answer is that he's racist. (or whatever '-ist' you want to describe this as, I've seen a decent case for ableist.) I know that's a really blunt and brutal description, and might feel a little mean to people who like the character, but it's really just where we have to start here: he is making this argument out of prejudice and feelings, not out of facts and logic, and we shouldn't look for the latter in it because it's just not there.

The Ascians' view of 'I don't consider you truly alive' largely comes from them starting at the conclusion of being superior and then backfilled their justification; there isn't logic to it, or at least not logic that would hold up or be in any way agreeable or sympathetic. Yes, the dragons fly in the face of this statement; no, that doesn't put any more logical holes in his statement than there already was, because it already wasn't a statement made with logical grounding.

Some argue that when Emet's saying this, he doesn't really believe it and is mostly just convincing himself. I've never seen clear proof of this, nor do I necessarily think that makes it better (might actually make it worse, in fact, because now it's just him knowingly dehumanizing and justifying the murder of humans)... but also most of the Ascians seemed to be on the same page on this, so it's not exactly dismissable just because Emet might be lying.