Well, they're breaking existing laws sort of, but also not sort of.
The problem I've seen is that all the laws specifically say things like "taxi" or "livery" or "limo service" etc.
Uber says "we're not one of those things. We're a ride-sharing service. Ergo the laws don't apply."
States/Munis/etc come back and say "wait, but you're giving rides to people for money. That's functionally a taxi service, and you're subject to taxi service regulations."
Then Uber stomps their feet and says "no no we're a ride-sharing service and your silly laws don't apply to us!"
So these new laws are essentially clarifications to existing laws, just with the scope broadened to include "ridesharing" services, so Uber can't crawl through the "we're not called a taxi, so we're not a taxi" loophole that the older laws have.
Certainly, some taxi regulations are awful. The whole million-dollar-medallion thing in NY is kind of insane from the perspective of elsewhere in the country. But not all taxi services are evil and incompetent, and not all taxi regulations are onerous. My own municipality has pretty decent taxi services, including a few app-enabled ones, and they're subject to regulations that I consider pretty reasonable - you have to serve the entire city, not just the rich parts (and the city subsidizes low-income riders), all drivers need to be trained to work with disabled passengers, and everybody needs insurance.
Frankly what bugs me most isn't that Uber wants to change laws, it's their way of doing it. Their shoot-first-check-the-laws-later methodology I think makes things a lot harder. Certainly here if they'd sent a rep to the city council and said "we'd like to start operating here" half the alders woulda fallen all over themselves to write exceptions into the laws and so forth. Instead, they just started running, thumbed their noses at the city regs, and basically alienated all the people who could make their lives easier. They might be able to pull that in big markets, but it's a lot harder in smaller ones.