Like Tony, I had noticed this clever idea when this picture was posted.
I have always been able to force things. Maybe I used the tool once popular on drum brakes, part of which is a stout rod whose end is ground concave: push the tool through the loop end of the spring, place the concave part on the post, and raise the rod (which acts as a lever with a nice mechanical advantage) until the spring loop slips along the rod and off the end and over the post.