Because they are designed to be somewhat 'plyable' - hopefully to be in the elastic deformation range.
Excess would have been mild. You're looking at the repaired state - NONE of the seating area inside my Sharpie brand dyechem

wasn't even there prior to my welding that material there.
Seized? Yes - IMO there was not enough clearance between the bolts and the sleeves. Spent about 30-40 minutes polishing the bolts so that the clearance at 'room temperature' is adequate. An additional disappointment was that with the TC cam plates, the back 'cup' on the rear cam, has about 50% of the purchase they had originally.
While I was working on them I texted a friend that spent his life building race cars (Indy, NASCAR, SCORE and SOCOM).
MEETS OR EXCEEDS MFG SPECIFICATIONS.
I can see in my mindseye the drunk fucker in a Las Vegas strip club who first coined that phrase at one of the first SEMA shows.
I would like just 1/4 of the time that I spent filling in the gouges that those first gen TC Lower Control Arms gouged into those lower perches. It wouldn't be bad if you could get a grinder in there but NOOOOOOOOO! - combo of grinder and files.
It's time like this that I TRULY appreciate the time and money that you guys spent on real cars. 
I've said it way too many times but after working in product development an proof for production for both (what was) the Big Three's (Aircraft and Automotive), the aftermarket testing program centers around 'Does it fit?'
EDIT: Regarding 'bending with hand' - this is an issue I see with MANY designs. Many folks have it in their head that metal shouldn't move. That is just the opposite. Metal should not crack! When you design things to embrace the properties of the material - Metal should bend in the elastic deformation range (so it snaps back) not the plastic deformation range (causing localized hardening and then - cracking.
If you really want to see a prime example of this, look at plane's wing. When we design wings, on the Destructive testing, we would bend the wing until it fails. If you want 'rigidity' it's done by triangulation or thickness but it will never be perfectly ridgid.
Another challenge that I have is where people think Class 8 or higher bolts are better. I think they have a place but not always in all places. Suspension is a classic example. - They are not good at stretching and go right into cracking!