If you want to change an entire industry, then yes. Sometimes it's better to ask for forgiveness than permission.
Uber has opened up the ride-sharing market to many more people. You don't need a $1,000,000 medallion to make money as a driver any longer.
Since the monopoly has been forcibly broken, it also created competition, which in turn lowers the price for the consumer.
It's a win-win. They are only breaking laws protecting unethical business practices of the taxi cab companies.