Upper A-Arm. Why pivot bushings?

[Desmo]

I've been searching the internet to find an answer why FF's upper a-arm has pivot points but no luck.
Isn't it better to have a fixed, rigid upper A-arms? Please help me understand the engineering behind it.
Does the torque generated by the braking cancel out the rearward movement of the spindle? Perhaps that's why the upper a-arm has only one non-pivoting point?

[Jim Schenck]

The clevis points on the upper arm are for alignment adjustments and are not pivots. They only can move as the arms are adjusted but once the lengths are fixed and the clevis bolts are tight the arm becomes a rigid part.

[Desmo]

Oh I see. That makes sense.
Thank you Jim!