I think Vettel had to have some kind of punishment because there was almost an accident there, but at the same time it is harsh.
He's doing what 200km/h, it's not like he can brake on the grass, and momentum carried him out towards the wall. As the commentators have said, he was still fighting the car.
If Lewis was 1 second further back, I don't think Vettel gets a penalty. As I've said before in threads, it pays to build a gap.