it makes you feel better, the fish has only been documented doing this once in 1997, and it could have been a hoax
Originally I thought the fish only went up there if you peed in the water, but that too seems questionable...
But it does seem to like swimming up women's hooha's. Just don't be a woman and you'll be fine!
Im not sure im going to explain the well, but...
I think they backed into the pole and it bent the bar (or whatever that guard thingy is called) up and under so much so that the pole ended up behind the bottom rail of the bar. The metal bar, then, spang back into place somewhat. And the pole "bent" / angled backward (from the ground). When the trucker tried to moved forward to get off the pole, the pole got snagged in the hole due to the spring action and got ended up getting dragged back to its more upright position, and it ended up as you see it in the picture.
I dont think the hole in the ground from the pole is from it being dragged forward, so much as from it being pushed backwards.
Edit: someone I know that has family that drives trucks says that it also could have occurred if the other trucks on the side weren't there to begin with and the person was trying to turn and the trailer swung out and the pole got dragged past the first hole and into the second hole. I'm kinda skeptical it could happen that way considering the direction the pole was dragged in the ground but who knows. it's just another perspective. But he also thinks the picture is photoshopped so...