If the 2 paint chips shown are the damage being claimed, then I don't see a problem. Only a scam. I regularly rent SUVs and nearly every single one of them has damage to the rear bumper from loading/unloading. None of which is documented, and none of which have I ever had issue with. That falls under normal wear and tear.

If I ever had this issue I wouldn't pay squat, and I'd do a chargeback on my credit card if they tried to take the money without my consent. They can blacklist me all they want, because this is BS.