'The Olympics, though, were started to further internecine wars and then national rivalries.'
That's probably a Marxist interpretation that I am not aware of.
The Olympics brought all competing states together and suspended any struggles they had. It was a celebration of sporting prowess and human achievement and internecine rivalries were put on hold.
Children are competitive from a young age. They grab each others' toys etc. When very young, children are egocentric, it is only as they get older that they understand the needs of others and become more cooperative.
Socialism is good in theory, but often in practice it ends up being run by competitive humans who try to brainwash the rest of the population that competitiveness is bad, so that they themselves gain greater power. The danger of this is that it leads to nanny statism, where the great and the good socialists know what is best for everybody else. They plan what is best for the ordinary people, just like the elitist Fabian socialists did, with their support for eugenics. They know what's best and freedom slowly dies.