Well, way back in it its early days, the then-Confederate Air Force had some incidents where they were accused of that sort of thing, paying for those in aircraft and blood. I'd like to think those losses forced them to be more responsible and safety conscious. In this case, the P-63 pilot appeared in one video to be following a P-51 who was also not only outside the primary line of mostly bombers, but flying faster than they were. Had they been at a different altitude, probably would not have been a collision, and I'm guessing that P-51 pilot has already had some explaining to do.
I'll grant that it almost looks like it could be deliberate, the way the P-63 hits the B-17 right in the middle of the fuselage behind the wing, as though he were trying to ram, but I'm not ready to go that far.
On the other hand, I was unpleasantly surprised by the NTSB preliminary findings of the previous B-17 crash, the Collings Foundation's "909". I'd seen their planes and people a couple of times before, and they seemed not only very professional, but well-resourced. But there appear to have been serious maintenance deficiencies blamed on the now-deceased pilot, which I wouldn't have expected to be allowed to happen.