ok so I agree with all this...
and not trying to be argumentative or anything but....
I think people assume that the cat will hide that recessive trait because until recently it was "thought" (I was one of these people) that all hiddens are always more recessive to the shown trait and therefore it MUST have that recessive there in the BG. It was not clear that your hidden can also be the same as the shown - a pure breed.
It will take some time for this to filter through the community, but I support all you say, and politely IMing ppl that they are incorrect and explain why is a good way to start