Sorry it took awhile but I fit tested my Thule 990 to the receiver on my 21, nope, won't fold up. Spare gets in the way. Still a great rack, just has to come off when I'm not travelling with a bike.
Re: thoughts on the "expert": IMHO, the Thule rack is heavy duty, built strong and I surmise durable, I have no hesitation to use it on a trailer. My Swagman platform rack is definitely an "el cheapo" and survived 25k miles on my 19. Still looks and works ok. I do bungee the bike on just in case.
Some who wander are not lost...