The problem is not in democracy itself as a concept. In both the open-source world and in society itself, the problems arise only when the demos (the population) either grow disinterested in democracy or is small in numbers.
As for "tyranny of the minority" - I hope to never see that phrase again. Protections for minorities in democracies exist for a very good reason. In the case of projects such as Debian to reduce the chance of solo maintainers quitting over frustration about being overruled, in democracies to prevent atrocities and hold up human rights for vulnerable people (e.g. disabled).