Yes, you're right that it's selfish, but that's also fundamental to competition. Winners take the glory that losers don't get. People enjoy winning more than hard work. So do groups of people: sports teams, governments, LLCs, etc.

Gamers often abuse the matchmaking systems to get this result themselves. They make "smurf" accounts in the competitive games they like, underrated for their skill level either from being new accounts or by intentional losing, because it let's them bully less skilled players and avoid being bullied themselves.