1) Because he's attempting to come up with an irrational insult to throw at you.
2) It probably was the 'worst' he could think of. Doesn't mention if the friend is a guy/girl, so it isn't inherently homophobic. More like he's just calling you handicapped.
3) It seems he had to return the insult.
4) Normal for a lot of people.
Green: He is upset too easily.
Red: The subject was titled, "noob? your gay!" So I thought he ment it as though the friend was a guy.
Yellow: I don't think noob is an insult, I just think of it as a title. It is not a title to be proud of, but a title non-the-less.
Blue: He should enjoy those PMing abilities, I would not have made this topic and just had an Internet argument if Badspot had not taken my PMing abilities away. What i am trying to say is, yes I agree with this statment.