No one working for Big Tobacco thinks they're making the world better unless they're an idiot.
We likely disagree about the merits of the DEA's War To Destroy the Lives of American Meth Users. That's a topic for another post perhaps, but the point is people have wildly different moral frameworks.
I'm sure there are people working for Big Tobacco who think they're making the world better by helping people enjoy themselves. Heck, some people who work in online gambling, or sports betting, or run state lotteries, or make ice cream, might even believe that!
Do they, though? Some of it, sure, but enough to make a positive impact? Probably not. Indeed, efforts to get drug X off the street often lead to a proliferation of more dangerous drug Y. There's plenty of reason to believe the DEA is only making things worse and causing more deaths.
It also brings up another truism: if you are fighting inanimate objects or god forbid abstract concepts you are going to lose just like a drunk boxing with a lamppost.