Do the Olympics promote peace? No... Not so much. Now if politicians had to be the ones on both sides of a war right on the front lines doing the actual fighting - THAT would go a long way towards peace.
As a side note... I read where some residents of London were complaining because the gub-mint was installing Anti-Aircraft guns on the roofs of their apartment buildings. I would gladly have my government come over and install an AA gun on top of my house, and maybe some Anti-Tank guns in the front yard and some artillery guns in the back while they're at it.