Talking Door Racing
If it did take out the whole field, it would have been a different penalty. If we live by speculations any contact would be a DQ.The only thing I have to say is I don't think a 20 seconds penalty is enough for a "red zone" restart incident. Each of those shunts could have easily taken out half the field. Maybe something to carry over to the next race.
I know it may sound harsh, but if you look at Kvyat incident for example, he had a stop and go for literally taking out a driver. Was it enough to compensate for Vettel, maybe (probably) not, but it was a fair decision.
Of course if it happens again there will be a harsher penalty. As it will clearly demonstrate a specific driver (not naming anyone here) can't handle the proposed race conditions.