a) Technically, one could argue he did not. However, one could also argue that the risk was there and perhaps there was room for leaving the move for safer circumstances. We are now realising how many of the riders have commented about the danger on that part of the track.
b) We cannot and should not take the speed from it when comparing with other incidents. The speed had everything to do with the huge crash that occurred.
So the comparison falls flat IMO, and this is likely why the incident you're comparing it to didn't lead to a spectacular crash and this is the blind spot with Zarco to which I refer and argue. What's with all the awkward incidents over his relatively short MotoGP career?
You may ask what incidents I refer to, and I feel a bit motivated to look into them to better support my opinion, but it would take too much time and effort. I have felt this way about him a long time ago. The only difference is that initially, I thought him careless and not really taking due care with his fellow riders. Now, I think he genuinely lacks that extra awareness on the bleeding edge of speed and while fighting with the other riders. That extra element of judgement that goes with his ambition during fights to move up the field during a race. He's very brave and very daring.... above average on the grid, I think, but if he's going to be like that, he needs that extra awareness.
MM is a great example of a rider that can carve his way through his fellow riders without causing a major incident. A few may complain about his aggression.... but there's typically no incident. Note that I didn't say "never an incident", just typically no incidents, i.e., big crashes.