I really don't understand why you think that you've been lied to. The hydro crack process is a synthetic process. I think that you're splitting hairs. This whole idea of Mobil One not being synthetic might possibly be nothing more than idea of the marketing people for one of their competitors.
That said, the beautiful thing about our free enterprise society is that you can buy whatever you want for whatever reason you want. But, I would be careful that I'm not cutting off my nose just to spite my face. Good product, proven and at a reasonable price.
Each to his own.
Have a great day,