I am curious, why do you think that this match will "ruin boxing forever"? In which sense? Personally I don't see this as much more than an exhibition match, some sort of experiment on cross-discipline fighting. Beyond the hype and the money involved, I would be interested in seeing how McGregor's skills translate to a boxing-only fight (not expecting him to win the bout, though).
RE: Why Boycott Mayweather Mcgregor