this makes no sense. if a store owner is selling a computer, why would they deny someone purchase of it.
Because they have some irrational prejudices? What aren't you getting here?
and furthermore if the computer isnt for sale then it isnt a product anyone would be asking to buy anyways
Why exactly do you make a distinction between "for sale" and not?
Say I hate furries, and don't want to let a furry buy one of my Rainbow Dash plushie dolls. I simply tell him its "not for sale" because its not (to him). Then when a brony comes up to me and asks for it, I tell him he can buy it, because it
is for sale (to him).