The outlaw motorcycle gangs that started Sunday’s deadly shootout in Waco, Texas, aren’t exactly extremist groups, but they share concerning similarities, a Kansas University expert says.

Such biker gangs don’t exist for the purpose of pursuing political goals, and they may not have a fully elaborated ideology, said Don Haider-Markel, professor and chair of KU’s department of political science, who researches extremist groups, terrorism, public policy and American politics.

However, they’re motivated by a “world view” that’s similar to a political ideology, Haider-Markel said.

Don Haider-Markel

Their primary philosophy is the pursuit of freedom, he said. They commonly engage in drug and firearm trafficking crimes outside the public eye (well, usually); they often share “old notions” about women’s roles (they’re mostly excluded from membership); and they crave brotherhood-like camaraderie (the gangs attract many ex-military and police officers).

“The reasons why people join these groups is not unlike the reason people join other groups: They want to be around people like themselves,; they want to have that social interaction,” Haider-Markel said.

Of millions of motorcyclists out there, only a small fraction join these outlaw gangs, Haider-Markel said.

Somewhat ironically, the pursuit of freedom leads to organizations with rigid rules.

“A belief in freedom, sort of outside the norms of normal society life, is part of what attracts them,” he said. “At the same time, the clubs provide this structure, because they have their own set of rules and elaborate indoctrination processes.”

On Sunday, nine bikers were killed during a shootout at a Twin Peaks restaurant in Waco.

As of Friday, 170 people stood charged with engaging in organized crime, according to national media reports. The shootout involved at least two rival biker groups and police officers, though it’s not yet clear whose bullets killed the bikers, according to national media.