Ocon was perfectly entitled to try to unlap himself and overtake Verstappen, it's within the rules, he checked with his team beforehand. He was on fresh tyres whilst Verstappen was managing worn tyres.
Ocon was racing Verstappen for position but Verstappen was not racing Ocon, he had a lap in hand, he was racing Hamilton or should have been.
In a classic two part manœuvre Ocon positioned himself on the outside of Verstappen being careful to give him the apex and room so that on the next corner, he was on the inside and the apex was his. Ocon had effectively won the corner.
Verstappen had three choices, having effectively lost the corner to Ocon, he could:-
1) Turn in for the apex, as if Ocon was not there, collide and risk not finishing.
2) Give Ocon space and the apex, mitigating risk and maintaining race position.
3) Drive straight on and not attempt the corner to save his tyres at the risk of picking up debris.
Immature Verstappen, with no thought for the potential win, against all common sense, turned in and collided with Ocon when there was absolutely no need to do so. Completely out of control.
Ocon was thinking incorrectly that Verstappen understood that he was not racing Ocon and so would not contest the corner as if the race result depended upon it.
Of course, after the race, Marko and Horner defend their driver! But what do they really think of his poor judgment?
The commentators and journalists mindful of Verstappen's temper, immaturity and lack of control - also that Ocon has no drive in 2019 - find it easier to condemn Ocon who was technically assaulted after the race was over by Verstappen to very muted criticism excused by Red Bull.