Actually, it is. The wet markets are known to be lacking in the most basic hygiene standards and sell disease-carrying wild animals for food and traditional medicine. They are also known to have some barbaric practices such as skinning animals alive. 'Medieval' being used here as an adjective to mean behaviour that is wildly outmoded or from times past.
For what it's worth, I think the people having a meltdown on Twitter are beyond pathetic. Special contempt reserved for the person sneering 'Wet markets are not by definition dirty.' But they are. That's the point. 'Eating bats is not by definition dirty.' But it is - they carry many diseases, including COVID-19. This has been scientifically proven.
I don't actually have a strong view on whether Morrissey's comment was racist or not. I just think he knew what he was doing by lobbing the word 'subspecies' in there, and that's my point.