In the case i'm aware of, law enforcement was investigating criminal violations of local ordinances by unlicensed uber drivers.
While i'm sure not a felony, that's definitely a criminal investigation they were seeking to stymie.
"Operating without the required licenses is a second-degree misdemeanor. Illegal drivers face a fine of up to $500 and/or 60 days in jail."
I'm not sure why you believe they are civil. They pretty much never are.
(Your example is not close to what happened here, as again, that would have been more okay. They did not warn the drivers. They hid the law violating drivers from the cops when they knew the cops were looking for them, and did so to make themselves money. It would be more akin to being able to change what the cop sees so that, at your command, all he saw was people going the speed limit, and nothing else)
Also, given how often Uber is brought up in these forums for ignoring/breaking local laws, I really would not be surprised to find that they have committed real crimes. I would be far more surprised if they had not.