Thank You for Smoking does a wonderful job of showcasing the elements at play in Washington DC and the power of advertising. Though there are though that take it as a clear show of what is wrong, in the world of advertisement and politics. I see it more as a showcase of what you get when you let things happen. None of the characters truly do anything arguably wrong, as while there are moral and legal implications. The social norms that were set and the world they where operating in forces them to do so.
For me it showcases what can be done when someone knows how to speak to the person in front of them and audience they target. The lead character explains it himself, he is just really good at talking. So really a lot of the criticism he takes through out the movie, is almost out of envy that their voices are not as strong as his.
The tobacco industry did a lot of shady things in this time and times leading up to it. But put in the same position I couldn't see anybody else doing anything different. If you were the owner of a tobacco company, and you were facing a threat like they were. Would you not do everything in your power to prevent it. Even if it looks bad from the outside, it is hard to say their intention wasn't good for their own. I don't like how things are done, but like the movie shows at the end it's how they are done. So you either play the game, or try to change the rules. But don't be surprised when the other players, play their hands.