Even with a car forum, where 99% of the content is about a single marque (forums.jag-lovers.com) you still get flame wars and tensions within the community.
You personally might not think that the choice of an air filter brand can get people riled up, but believe me, it can develop as much divisiveness as any political issue.
Within any group of individuals bound by a common interest there will always be tensions. To me the trick as a moderator is to tolerate debate, even passionate debate, while keeping an eye out for when people start to get personal.
There will always be users who goof off, and derail anything.
There will always be users who get personal, (rather than arguing in the philosophical sense).