I'm not sure I agree with this lesson. I've sunk 1000s of hours into DOTA 2, and would agree with you in such a game where emotions run high and considered, reasoned responses aren't possible, but I think it's a poor takeaway from the game. Sometimes it is correct to stand your ground and stand up for what you believe is the correct course of action. I'd instead emphasise the importance of emotional control and the importance of morale as a better lesson from MOBAs.