How are there so many Exiles and Outlaws?

Yeah, but we are talking about being there for a year or so. That is such a short period of time for the vast number of gangs, organization and settlements they have had. Very hard to believe.

You never know how people are going to react to a crisis until you're in the crisis. You have people who were promised seven "golden worlds" that they'd be able to start settling. Instead what they wake up to find is that their vessel has been shredded by a dark energy cloud, killed an untold number of people, they're left with incompetent leadership and insufficient supplies, and none of the worlds are suitable for colonization.

And once you throw people out of civilization, they tend to get uncivilized pretty fast. When life becomes a struggle for survival, people do what they need to. When they find themselves in a situation where the rules no longer apply, they tend to have a moment of realization that they no longer need to inhibit themselves. Also Lexi figures out that a lot of the exiles are suffering an unforseen side effect of cryosleep that has altered their brain chemistry and heightend their aggression and antisocial behavior.

What I want to know is: How is it possible for me to clear an area of Outlaws, only to drive by 1 minute later, to find them back again. Cloning?

the excuse is that they suffer from cryo sleep mental illness that makes them go nuts. Thats literally how the game explains this away - its actually not as bad as killing thousands of them considering that there are less than 100K milky way people in Andromeda. 

Kadara itself is explained as an angaran port liberated from the kett by the Outlaws

The Outlaws are evidently capable of great things.  Indeed, they were the ones who achieved First Contact, not Ryder