What makes me shudder is every time I get passed by some overloaded, hot-rodded, crew cab diesel 2500 towing a 40' 5er going 80+ mph with their hair on fire. Far more people are killed per year by this scenario than by someone pulling an RV with an HDT.
Just because the owner's manual says it can do a thing, certainly doesn't mean it should.
And yes, 25k+ campers are quite commonplace. Most are designed so poorly, to keep the pin weight down for 2500/3500 rated cargo capacities, they handle terribly. A trained driver like yourself would be shocked at the (lack of) balance on a scale ticket from one of these rigs.
I'd rather take my chances with an HDT stopping this rig than a 2500 with 4 big mud tires and a coal rolling tune. But, hey, at least they have $100k in that fancy pickup.