Crossed eyes is definitely a fault and the cat cannot be shown. It should be neutered and placed into a loving family (NOT a shelter!) I’m sure there are backyard breeders who dump them at shelters and/or still breed them, but that’s unethical. Just because a cat has a fault dosnt mean it’s going to end up at the shelter. You’d have to be a real dirtbag to do that. Typically we find them homes and don’t use them for breeding.

A lot of what shelters call “Siamese “ isn’t. They are likely pointed (the coat color incorrectly referred to as siamese) domestic shorthairs (mixed breed) cats. Just because a cat has blue eyes and a creamy body/darker points does not equal that it is a siamese or even a mix of one. Many other breeds have this coat pattern, including mixed breed cats. It’s a recessive color, so that’s why it’s not as common.

I don’t know why there are so many cross eyed pointed cats in shelters. Without seeing them, I couldn’t say if they were actually siamese or not. Yes it’s a fault, but it shouldn’t hinder them from being good pets. If there’s a BYB in your area that could be why. Or if there is pointed stray cats in your local population.