1.) Levels of toxic and/or malodorous substances that you're happy to belittle as being no big deal
are unacceptable by many.
2. Not my problem, and it shouldn't be. I like to listen to loud music, and I make sacrifices so that I may indulge my pleasure without harming others. It's called being a responsible adult.
3.) Not my slippery slope.
The last time I checked, in the US it was mandatory for cars made since the late '60s, and catalytic converters since the late '70s. These standards are getting increasingly tough. If car owners can live with it, then so can tobacco smokers.
4.) There's smokeless tobacco, gum and patches for the addicts. You don't have to smoke to get your fix.