I actually haven't bought Castrol in over a year because of feelings about the Deepwater Horizon spill after I watched two in-depth documentaries about it and learned more. However, I feel that the fines sanctioned against BP ranging in the billions of dollars far outweigh anything we could ever do as consumers. I have had excellent results with GTX and think it's a fantastic product. Frankly, I will be buying a jug of GTX today and basically nothing will change except I'll have the oil I like. BP stock won't jump due to my purchase. Life, both human and animal, that was and is affected by the spill won't change.
What happened has happened, and it's a terrible, terrible thing. But Shell and Exxon (the two forum superstars) are far from innocent themselves and I always find it hypocritical when a loyal PP or M1 buyer criticizes a Castrol fan for their choices.