The Perfected Society

Most gnomes are scientists at heart. They poke and prod at natural and magical phenomena just to see what will happen. Usually, this ends badly for them, and most of the other times it ends with something functional, but useless. Occasionally though, they find something worthwhile. When that happens, the entire gnomish community tends to adopt it enthusiastically. That worked out fairly well for GnomeJets (which are an admittedly faster method of moving through the phlogiston, and are now much less prone to exploding). Its effects with social science have been somewhat more mixed.

They're racist now.

It's not that most gnomes actually dislike anyone, even someone who happens to be taller. They just felt that as part of their new nationalism, they really ought to celebrate the historically unique aspects of gnominess.