I think it might be a sort of hypocrisy in the show that the Federation is multicultural where all cultures are equal but humans are in charge.
Humans are not "in charge". Remember, the last President of the Federation that we saw was a Grazerite. And there are plenty of aliens in the leadership of Starfleet and the Federation.
True, the main government apparatus is located on Earth, but who cares? The capital has to be somewhere...
J. Allen wrote:
Because I would engage in sexy times with them.
Dude, you'd even go "mounting and finishing" with the Enterprise