because there's never been any real intentional breeding done on default cats. if we've fucked up their genetics, it wasnt because we bred them, but because we killed very aggressive ones and kept the cute kittens. much of the evolution of cats among humans was done not as pets but as barn cats (or similar roles), where they are a half-tame half-wild animal that fucks whoever it wants.

cat coat color clearly has nothing to do with anything. the wild cats from which domestic cats come from are all basically tabbies, and it's not like anyone set out to breed cow-spotted black and white cats. all these coats coexist in feral/rural (the line can be hard to draw, with barn cats and such) cat populations and it's just random variance.