I'd rather say that, once again, no one can prove that Alonso did anything wrong.
Unfortunately, no one is omniscient, so we can't deal with 'what ifs'. We have to deal with the race as it unfolded, and in that race, Alonso was wrongly gifted seven extra points.
I don't see how this is really in question. One is free to think that the ban on team orders is absurd, but that doesn't mean that the rule isn't currently valid and a team which is caught doing it is free of punishment. The same goes for the argument that 'everyone is doing it'. If others are doing it, then they should be punished as well, not the other way around. Both are cases for leniency, possibly, but not for outright dismissal of the crime.
I think the best one could argue is that Ferrari were the victims of hypocrisy and selective prosecution. But prosecuting only the more blatant transgressions isn't selective prosecution. Were I to get caught speeding at 50kph over the speed limit, I couldn't get off by arguing that the police didn't also ticket everyone who was going 5kph over.