The argument of (1) doesn't really have anything to do with humans or antromorphising. We're not even discussing AGI, we're just talking about the property of "thinking".
If somebody claims "computers can't do X, hence they can't think".
A valid counter argument is "humans can't do X either, but they can think."
It's not important for the rebuttal that we used humans. Just that there exists entities that don't have property X, but are able to think. This shows X is not required for our definition of "thinking".
If somebody claims "computers can't do X, hence they can't think". A valid counter argument is "humans can't do X either, but they can think."
It's not important for the rebuttal that we used humans. Just that there exists entities that don't have property X, but are able to think. This shows X is not required for our definition of "thinking".