Tobacco companies graphic label requirement? How does that violate free speech?

As I understand it, the government is trying to require that the tobacco companies show graphic images on there adds. They (the government) hope that it will turn some people away from tobacco. I would like to know just how it violates free speech if it's the truth.

It's true that tobacco companies have the right to say whatever they want about their product but they should also have to say (and show) the harmful side of using tobacco. Just like drug companies are required to list all of the side effects of their medication on their adds, tobacco companies should also be required to show us what using tobacco can do to us.

I do think that fewer people would use the product if they did that because they would see before hand what kind of effect it has and they wouldn't have to find out later when it is much harder to quit. Tobacco companies make their money by taking advantage of us.

Even though I may have understood that story wrong my opinion still stands. We should make the tobacco companies show us the harmful side of their product before we start using it and then we can decide whether we want to do that to ourselves or not.