Stupidity is just a opinion and being legal does not make it stupid.
I'm really amazed at some RV folks lack of knowledge where a legal or safe rv double tow is concerned.
However with no tow vehicle size...... and how much weight was the so called 40' footer..... and what is a so called full size car or its weight its just a personnel opinion. I've noticed some folks from states that don't allow rv doubles get all wrought up when they see one and report it as dangerous or stupid or some other description .
Around here double towing rv's is very common. Nothing stupid or dangerous about it.