People with the aptitude to become community or project leaders often like a good debate (OK, sometimes it seems like an argument), and will often provoke it, if only to see how well the point can be defended. When the chips are down though, rational decisions based on facts is what wins.
I may not be as gruff as some of the more infamous names around, but I will often argue a point, as well as play devil's advocate, just to see how the debate plays out. I learn a lot that way, whether I'm correct or not.
[Edit] Re:Linus I agree that Linus' reply was a rude, and perhaps I've been desensitized to this over time, and let it slide too often. My comment however, was meant for the more general case to which I replied.