I didn't call you an enemy. Yes other users are outraged, use the search button. No, it is not discrimination to refuse to service owners of a certain automobile, any competent attorney can tell you that. That would be like saying it is discrimination because iPhone Apps don't work on your Android phone. The store does not have any legal obligation to give you the reasons, and they may not have all the information. You do not have a right to rent and pull a trailer, they are offering a service, and they are not discriminating based upon skin color, beliefs or anything else. They are simply refusing service to a specific vehicle, something you could have found out before even making the decision to purchase the vehicle. It is nothing like not giving you a seat on the bus, you weren't born a Ford Explorer owner, you made a conscious decision to own one.
Honestly though, I was surprised myself to discover this. I've rented trailers before for my explorer from the U-haul dealer here in town, but he always rented me the trailers he owns privately, so I hadn't realized this policy was in force.
But seriously. I don't think you are an enemy or anything, I just think your comments are making light of real victims of discrimination, and I don't like that.