Comment by gcanyon

They only look like they're made of meat. And they only look like they're made of meat to you because you know you're made of meat, and they look like you.

To them, they're just disguised as "what the creatures on this planet look like," which is obviously (to them) not meat, because they've never seen meat beings. To them, we are obviously not-meat, although how we appear is compatible with being meat. But silicone dyed the correct shade can look like meat. Stone painted the right color can look like meat.

And if you say that silicone and stone don't look like meat even when prepared to copy it, bear in mind that we are made of meat and very good at distinguishing it. Different races favor different attributes for distinguishing one person from another, hence why "they all look alike" is somewhat true for pretty much any "them" you care to name. Rocky from Project Hail Mary almost certainly thinks all humans look alike.