Yes it's bad but let's put it into context
Piquet crashed his car into the wall so his team mate could win a GP.
Senna admitted crashing into Prost to win the World Championship and it was also premeditated.
Schumacher crashed into Hill to win the World Championship.
Schumacher crashed into Villeneuve in an attempt to win the World Championship but failed
1994 – Bennetton under the control of Briattore/Brawn tampered with the fuel rig to get faster pit stops resulting in a fire that burnt numerous mechanics
In all but the Piquet Jnr incident other parties were involved in the actual incident. At least Piquet had the good grace to only involve himself – yes there might have been others involved such as marshals if it went wrong but same can be said for the other "accidents".
Oh, and I thought the ban on refuelling was to do with cost cutting and not having to transport all the kit around.