In 89 that was Prost that intentionally ran into Senna, not the other way around. And he put pressure after the race to have Senna disqualified for using the escape road of the chicane instead of put the reverse and make the corner, while any other people that missed the braking point that year and years before used the escape road without beeing penalized. That is how Prost won the championship that year.
1 year later with the reverse situation in the championship, Senna told Prost he will put him out of the race if he has the chance, as a payback for what he did 12 month ago.
Now back that penality, it is one of the stupidest one ever given. Several driver in the past rejoined the track like this and were not penalized. The most recent one was Grosjean in the 1st corner of the race: this one was very dangerous with a lot of car with any visibility making the corner and Grosjean rejoining the track like no one was there. He had full control of his car and should have wait and rejoin last. Did not do it, nearly collide with a Racing Point and it was not even investigate.
Hamilton also did things like this in the past without being worried and while he had full control of the car
He cut the chicane, rejoin, then nearly put Ricciardo on the wall and forced him to brake to avoid collision. And that is only one example...
BTW Hamilton just had enough space to make the move. It would have been very close to the wall, but if he did not have braked, he would have overtake Vettel with a few cm margin. For sure he couldn't know that because Vettel was out of control at that point, and that is why he braked, cannot blame him for that.
On the other hand, Hamilton saying that he was not happy winning like that? Common, he was the very first one to say it was unsafe from Vettel. He knew that if he complain it will trigger an investigation...