That bolt likely was not seized in the beginning, there are at least two different designs used. One has the bolt with splines machined into it so that it grabs the knuckle when the nut is tightened. That one simply gets driven out. The other design has the bolt threaded through the knuckle, and its not uncommon to find it additionally locked with a nut. That can really throw a tech for a curve when you don't expect a nutted bolt to also be threaded through the knuckle.

The splined bolts are easiest to remove by installing the nut back onto the threads just far enough to prevent damage to the end of the bolt (flush, to the bolt barely recessed in the nut) and then drive it out with a hammer adapter for the air chisel. The other style of course needs to be unscrewed, and the impact wrench is the tool of choice.