Re: Starfleet is the U.S. Coast Guard
When the unthinkable happened and Earth entered into an interstellar conflict, the UE Starfleet had no choice but to adopt the mission of Earths defensive space force, and brought along the separate special forces of Earths unified army (although I still believe that the MACO were not a large fighting force. We know that the Earth nations still had militaries, so the MACOs were an elite fighting unit granted to the United Earth government. A small force it always had access too.)
So basically the MACO's were X-Com.
You perceive wrongly. I feel unimaginable happiness wasting time talking with women. I'm that type of human.