He was talking about viscosity, not what base stock is in your particular brand of preferred oil. As long as you change the oil regularly, anything you run these days should provide enough film strength to protect your bearings. The better quality synthetics will just do it for longer without breaking down. Well, that's always been my take on it...
If you change your oil regularly and keep the temps under control, it probably makes no difference if you run a decent semi or the best quality synthetic on the market, as long as the viscosity is within your engine's preferred range for the climate it runs in.