A mask can increase your risk if you use it improperly (e.g., touching your face more to adjust it, not washing it, using material so porous it has no effect, luring you into a false sense of security around people with the disease so that you no longer distance from them). On the other hand, a properly used mask provides some added measure of protection over no mask at all. So not an idiot, but I somewhat disagree with him on this.
My 3M N95 mask directions say you must shave everyday or the mask may not be effective.