I think for the sake of the championchip ONLY, the fine would suffice, although they should have fined Depuniet as well as both riders were at fault.
There should be a very clear line in the sand drawn - ANYTHING like this including stoners antics at every other rider on the grid (he seems to think he should have sessions on track by himself) will NOT be tolerated and will be met by severe penalities. At the the same time ALL riders should be made aware that riding slowly on the racing line will also not be tolerated and will also suffer severe penalties.
Finally they should string race direction, in particular Butler up out back of the pit garages and throw torque wrenches at his nuts all day on Monday & see how he likes being put in dangerous situations!
Problem is he doesn't have nuts as if he did he would have made the tough decisions when they were needed to be made and not been party to creating the mess and imbroglio we now have.
On a different note, but related. If they are to 'outlaw' any for of a rider showing disapproval of another's actions it will (IMO) lessen the sport immensely but they do need to be clear on what is acceptable and what is not and advise each and every rider, team manager and the media corp so that all know the line that has been drawn
It won't happen though
Gaz