Just a comment about vehicle towing capability data. This data mainly relates to the tow vehicles structural capability and it's engine/transmission capability to pull a give size load. These ratings in no way speak to the dynamics, control, and stability of the tow vehicle/trailer combination. There are so many variables involved in in the stability and control of the combined vehicles that are out of the control of the tow vehicle designers that it would be impossible for them to design a vehicle that would fit every concievable trailer/tow vehicle combination.
Having said that, the ratio of tow vehicle weight to trailer weight can be a factor in resistance to loss of control due to trailer sway. Towing a 3500 # casita
with a 7000 # Ford F350 will have more margin to resist a loss of control due to sway than say a 3500# Casita
and a #3250 Subaru Forester. Admittedly, this is not all due to weight alone, wheelbase also is a factor.(Generally sppeaking though, heavier tow vehicles have longer wheelbases.) Cerrtainly tractor trailer rigs have different (lower) weight ratios but thethey are more affected by wind and other tractor trailers than by RV type trailers. (And they regularly have stability problems due to winds and their ability to remain controlable in avoidance manuvers is really limited.) They however can really play havoc with small RV trailers.
So don't discount the additional safety margin that larger tow vehicles provide when pulling small trailers. But since we all can't have TV weight /Trailer weights >>1, we need to know the limitation of our rigs, use sway conrol devices, and drive cautiously and keep are speed low enough to minimize stability problems.