WDH - anyone ever told by dealer not to use?

Of course. You don't always need a weight distributing hitch. If your TV is robust enough and can handle the tongue weight you're not in need of weight distribution (your question does not speak to any sway control considerations). A very simple, but typical example, is a contractor friend of mine. His truck for his business is an F-450, which he also uses to tow his camper. His camper is a Roo 19, which is in the 4500# realm. You need to look in the mirrors of the F-450 to know the Roo is back there.