Resorting to petty names like fanbois, and now throwing wild assumptions around. At least don't use the word logic when you go on like that. Look at some other games - MP and SP coexist perfectly fine, and you certainly won't see people on their forums complaining how one will ruin the other. This is a syndrome I've yet to encounter in any other game community, and I'm part of quite a few of them.
Fanbois is no more an insult then being called irrational. I also used the qualifier "some". In general, most MP advocates have been quite well behaved.
I think Civ is a totally different animal then games like Starcraft II. SP and MP can coexist because really, in essence, it's a pretty simplistic game.