I saw that as well but I wanted a oem look and fit. Exhaust claps also may shift under a lot of stress
Actually, with the U-bolts mounted in between the shock mounts & with the clearances in there, the fit is really tight.
If there's a weak point in a driveline or suspension, with what I put my trucks through, I will find it!
How are you supposed to know where the limit is if you don't go out & find it?
Lol!
I'm under my trucks checking things or just fixing things that just don't need fixing all the time.
9 years of the sway bar on my '97, with U-bolts, & I never saw any evidence of it moving.
All the aftermarket suppliers, such as Hotchkiss, Adco, BellTech etc, all use the U-bolt method to mount their bars on non-factory equipped vehicles.
Plus, many of those aftermarket bars can be much larger/stiffer than the OEM GM SUV rear bars, which creates much more stress on the mount points.
IMO, the weakest point of the sway bar is the upper & lower bolts that go through the sway bar ends/uprights/frame mounts. Especially that bottom one as it has the sway bar only mounted to one side of that upright, instead of like the top one that's straddled on both sides by the frame mount.
With the stresses I put my truck's suspension through, I could see those lower bolts pivoting on the bushings & maybe bending. Or snapping when the suspension loads & unloads when the rear end breaks loose & starts bouncing as it kicks out. (Downshift, hammer down, steer into it & drive through the bounce!)
Those bolts had me keeping an eye on them more than anything.
So to ease my mind, I swapped out all four for for Grade 8. Probably overkill, but one less thing for me worry about.