Actually, the story doesn't say that it's machines if I can see correctly. It might just as well be other evolved organisms, just not protein/"meat" based.
Makes you wonder how can they have a concept of "meat", let alone such a dismissive one. We call "meat" the animal tissue that we eat as food- so either here "meat" is an inadequate term for "organic matter", or we have the curious case of an alien lifeform that eats organic matter while not being itself organic.
In any case, being non-organic, it's not clear where they might have gained such contemptuous familiarity with organic matter- although it's clear from the story that they know about it much less than they think.
English has separate terms for "flesh" and "meat" for complicated reasons, with "meat" having a stronger food implication. But I think the story uses "meat" because it's a funnier word in that context.
It’s not hard to imagine aliens knowing about organic matter since those are universal. I could see a disdain for it if that’s where they started and then “ascended”. Much like we might view crude stone tools compared to say the LHC. Or how we view a single celled organism.
