Actually, they are. But, more importantly, you are trying to decide for other people what's good for them. Some people might prefer a less safe ride with a less professional driver for less money. Now, I don't see anything wrong with informing people that private cabs might not be as safe, however the decision to use one should lie with the customer, not with the government.
How does an average person knows which restaurant to go, which shoes to buy, which ISP to connect to internet through, which car to buy, which computer to use and which city to live in?
Well, here in the UK, if they want to know about food safety then the star rating from the government mandated hygiene check is posted on the door to the premises, letting the consumer know the cleanliness of the kitchen and the safety of food preparation practices.
This, like car safety ratings, is something rather hard to judge by a cursory look around the place. We also consider these two things important enough for regulation as they can result in illness, injury or death.
Shoes, well, if your shoes fall apart very quickly then you have a statutory right to a refund, rather than a libertarian 'right' to bitch about it and hope to damage the business. Other things are regulated similarly.
It's not a question of someone choosing for you, it's a question of society coming up with standards and regulations to take the danger of unscrupulous or negligent merchants out of the picture.
