I participated in the event from 1991-1994. From my perspective, the majority of riders are all about themselves and their leather and iron and silly bandanas not MIA/POW. The event is a tool looking for a user.
Then it is good for Trump to be using it.
I’ve ridden Rolling Thunder a few times. Some are more sincere about the POW/MIA issue than others, but they’re generally good people and it’s a great ride.