Well they are two totally different events.My agenda? How do you explain that Hulkenberg got a penalty because if lost the rear of his car just a bit over the limit - it was nothing outrageous - in a wet track ruining Hamilton race but nothing happens to Vettel by doing much worse - it could even have ended his race -?
Hulkenberg wouldn't have got a penalty if he hadn't took Hamilton off. Hulkenberg knew that Hamilton was alongside and knew where the Caterham was in front of them, and there were no other cars around them. The Caterham didn't suddenly move over in front of Hulkenberg to cause him to brake too hard and lose the car. I'm sure if it was Kobayashi or Grosjean that had knocked Hamilton off and took the lead there would be outrage if there hadn't been a penalty.
The Vettel/Senna incident was on the first lap, it is expected there is a chance of contact on the first lap or two until they sort themselves out.
Neither Senna or Vettel knew where the other one was, both being unsighted by DiResta. Vettel made sure the car behind him (DiResta) was behind him when he turned in, and Senna was clear of the car he was overtaking (again DiResta) when he reached the corner. Both cars aimed for the same empty piece of tarmac without seeing the other car until it was too late, both unsighted by being either side of DiResta. That counts as a racing incident.