Look at the line drawing I posted, there is no slip joint for the torque arm.

You want both the pivot and the U joint to be as close to in line as possible. The point of the torque arm is to control axle wrap.

If there is a bit of movement the slip yoke in the driveshaft handles it.

They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.