Because you appear clueless I'll take a shot at explaining why this is super dumb.

Dealers provide a service just like the wait staff and they are not making a ton of money because they are expected to be getting tips. So not tipping them because you think they make a living wage is super dumb.

If you are morally opposed to tipping, knock yourself out, save yourself a couple of bucks here and there, but don't try to justify it by saying the dealers job is that much different than any other service employee.