People that decide to ride vehicles on trails in the woods whether foot powered or gasoline powered are searching for the same thrill and enjoyment in life. So this us vs. them mentality, I don't quite understand.
The original poster should keep in mind that many of the trails in Northern Jersey now enjoyed by offroad bicyclists were originally created by organized offroad motorcyclist groups. Read up on NJ motorcycle enduro racing and you'll find plenty of history.
Perhaps I have a different perspective, but just my $.02 that we should all try to get along.
-Scott