The source of the problem is that the bushing is wider than the sleeve that goes through it. It might not be when you look at it on your workbench, but when installed in the control arm, the sleeve will be 1/16" or 1/8" shorter than the unloaded bushing. When you tighten down the bolt it squeezes the poly bushing between the control arm and the xmember and its that pressure applied to the bushing that creates the huge amount of friction between the bushing and the sleeve, leaving it unable to rotate easily. John's nylock solution undoubtedly works to reduce the friction and make the suspension work better, but it may also let the sleeve rotate, so essentially the suspension is now pivoting on the control arm bolt itself instead of the bushing moving on the sleeve and the bolt locking the sleeve down securely. I'd fix it a different way: sand the ends of the bushing down - belt sander is great for this - until it is just about the same length as the sleeve that goes through it (when installed in the control arm). Now you can tighten the bolt to spec and the bushing works as intended. Also a good idea to drill a hole and install a zerk in the control arm so that you can grease the bushing later on. One way or the other, it's worth dealing with it. If the control arm is that hard to move, then they won't be reacting as quickly or accurately to smaller bumps on the pavement, nor will they allow the suspension to extend into dips.