You shouldn't be buying from Shell anyway given their history of human rights violations around the world. And in the more recent decades, their fight against eco-friendliness.
Of course all oil companies are shit, but for now it's a necessary evil, and some are worse than others.
That's always the problem with the "vote with your dollars" refrain: there's a race to the bottom where soon enough all the options start doing the shitty behavior.
The only solution that actually works is consumer protection regulation.