Of course if Veg is already hard to get in your area as it is I believe in many country regions, It would be completely counter productive to try to change this mechanics mind. Having him telling a whole load of people about Veg, No doubt a number of whom would want to give it a go, would put even more pressure on the supplies in your area and make things difficult for yourself and those already around you using veg.

Some peoples first reaction might be to want to turn this guy around to "
see the light" but those with a bit more intelligence may want to stop and consider all the ramifications of doing that and if the best thing isn't to leave things be.