That's not quite true, a few corners earlier the two of them had a coming together and both ran wide and off the track - I see this as a retaliation to that event just a few seconds earlier ...
Still wrong and indefensible and he was rightly black-flagged immediately.
I raced motorbikes for 10 years and the worst I experienced was accidental contact, banging of fairings, type thing and the only time you ever took a hand off the handlebar was to make a hand gesture or adjust the steering damper.
What makes this even more significant is the track for this race...
And Moto2, although on less powerful bikes, is just as dangerous without your competitors resorting to this ....
https://www.bbc.co.uk/sport/motorsport/45467475