I don't remember it being terrible, but that looks like it would make it super stable. We've done White Rim and plenty of other mild wheeling with it, getting back to the 24 hours course, Barlett Wash.
Something is gonna move so the easy to fix or replace rack is better than denting your bike frame or rubbing the paint off the bumper. You can see the rub marks from our bikes, there are matching marks on bikes that cost ten times what the rack did...
But OTOH you don't want the thing bouncing around breaking windows or falling off. Those straps are probably right the right balance.
"Stand your ground. Don't fire unless fired upon, but if they mean to have a war, let it begin here." -- Capt. John Parker