Disagree. Players running around sometimes collide accidentally, and if there's no intent to block, and no one gets an advantage (e.g. knocked down) then that's a no call - play on.
In this case, GC4 had no intent to block, he wasn't even looking that way. And he didn't "stick his butt out" he just pivoted. He was already bent over to protect the ball from the post defender. Had he been looking at Davison, and stuck his butt out to clip him, then I can see what you are saying. But that clearly is not what happened.
Davison ran into him ON PURPOSE - watch him instead of GC4 in the video as he chases Grill. He intentionally took an angle to NOT go over the top of GC4, and braced himself for impact. As he chases Grill he is moving to his left, then zigs right as Grill goes over the top, and zags left into GC4. There was plenty of space to go around, he just decided to run into him instead. That could have been a foul, but it looks like an accident in real time, so I can understand it being a "play on". I would guess this is something Gard coaches guys to do when they are already beat off a cut.
When Davison ran into him AGAIN, and knocked GC4 to the ground, that's an absolute foul on Davison. You can tell he reset himself to jump into GC4, arm is still braced for impact. Yet it was called on GC4, who got his 4th(?) foul for being hit in the back twice!
Unforgiveable error by the ref, and iirc took a 3 off the board from Grill. Watch it in slo-mo and it just gets worse as you see the intent.