It's a proven fact that THC is neuro-protective. meaning it actually protects healty brain cells.

However yo aren't entirely wrong, you're just a victim of propaganda, because THC DOES kill brain cells, but the only ones it kills are weak cells that aren;t supposed to be there anyways, it makes them die off sooner before they can mutate and become a tumor or brain cancer. So you're perfectly correct you just didn't ALL the info =D