I was at lunch today with some friends, and we were talking about the religious passions of various developer communities. My friend James (congrats on the new job, by the way) was talking about the varying degrees of religious passion amongst the different developer communities at his office. The Java crowd, he said, was much more into debating the merits of different technologies, and much more likely to be disparaging or dismissive of other technologies than the .NET crowd.
This echoes my personal experience in this area, so I offer the following analogy: The Java crowd is extremely passionate because of the level of choice in the field. Since all Java developers at some point have to make a choice (I'm a WebLogic/Jakarta/Struts guy, or I'm a JBoss/WebWork2/Fit girl, or whatever), that element of choice causes the emotional stakes to be raised. Conversely, being a .NET person is like being a citizen of a country with a state religion: if somebody attacks your beliefs, you'll push back, but you aren't out there every day trying to promote it. Why bother? Where you live, everybody is the same religion.