That's the sense I get from this post. Lots of emphatic proclamations, virtually zero actual argument. There's a statement that "consciousness is very likely biological"... and then that's it. No argument for it, no citation.

If you want to argue that AIs cannot be conscious, that's fine. But the argument has to take the form of something like "Consciousness requires this, this, and this, and these are properties that AI does not have and cannot have for this reason, this reason, and this reason."

I've never seen that argument. Because it basically cannot exist. Consciousness almost by definition is a subjective experience, and the only reason I'm pretty sure that other humans are conscious is that I'm a human and I'm conscious.

About your last point, I thought so too a few years ago, but interestingly the science of consciousness is an emerging field, although empirical testing is still hard to do (see for instance https://www.youtube.com/watch?v=j2zv4jlo2Nw ).