They have several messages:
1. Notify about their costs and hardship.
2. Getting taxes down [Americans have no idea how high they are in Europe].
3. Getting additional government subsidies.
I leave out any comments on point one. As for the other two: they won't help. Due to the energy market structures [producing, distribution and retail are essentially in the hands of the same companies; the actual costs to get crude and refine it are the same, even distribution costs are the same] and the simple fact that the market has already shown how high the proce can be, a tax cut would only hold for a few weeks, probably less than a month.
Subsidies are a bad thing per se, though there are obviously some applications where they make sense. Interestingly the energy market is one of them. But not for petrol. Especially not when the resource at hand is limited. What it would come down to is subsidies for lorries, which are paid through higher prices [either taxes on petrol or general taxes increase] by all other drivers. Then taxi drivers will want subsidies, then anybody who uses his car for his job ...
Eventually all drivers get subsidies, which would accomplish nothing. At the same time petrol prices will rise further since people can now pay more [it's not their money but government subsidies*] and they use more, hence increasing demand while supply declines**.
*For those not getting the irony: any government subsidy is the peoples money.
**Even if there is theoretically enough oil in the ground to last for a 1000 years, the problem is conveying it at a reasonable price. Supply has reltively little to do with physically possible, a lot more with reasonable costs.
