Most the time people just dont know, they just see a cute boy and a cute girl so put them together and make cute puppies lol.
When I had two rabbits(a girl and boy)I kept them separated while waiting to get the boy nuetered and a friend thought I should breed them so they could have a cute lil bunny, but I said no because I knew nothing about breeding them, and that was when I didn't even know much about rabbits.
But thats why before you do anything you should research it, because what you might think is right could be wrong, like this one time a friends kid was watching me clean out the rabbit cage and I caught her just in time when she was about to pick the rabbit up by the ears
so I explained to never do that and the proper way to pick them up and she said but thats how mommy picks up my rabbit
and I doubt she was doing it on purpous to hurt the rabbit, but that was "normal" for her.
So just saying I think most the time people are not informed, and then there are the time when it's on purpose, lol