Yeah, from what I understand most of the actual opposition these days -- and, to an extent, where support for the taxation comes from -- is the burden smokers (particularly under or uninsured ones) puts on the medical system. Not so much second-hand these days, barring the occasional crazy. Mind you, I'd rather imagine complaints about the smell have increased to some degree simply because people aren't as used to it (and you seriously have to be inured to the smell of cig smoke for it to not be incredibly noticeable), but the direct secondary health risks have been managed alright, imo. At least in the public sphere... parents screwing their kids over or whathaveyou is still common enough, from what I've personally noticed.
That said, yeah, if we're going to do vice* tax we should probably do it to everything of similar nature. Throw a tax on vidya games, if similar medical costs are identified, or whatever. I'd kinda' doubt it considering it's pretty rarely video games that are actually causing medical issues (if folks are sessile enough it's causing health problems, excessive entertainment investment is a symptom, not a cause), but if it is, treat it the same way.
Does logically lead to eventual lifestyle taxes -- people having a tax burden for not exercising enough, ferex -- but... okay. If you're going to go that route, then go that route. If you've committed to making people pay for non-optimal life choices, in order to offset the burden those choices place on society, go all out. Just make sure you've got exceptions for folks that can't maintain the par...
*Which would probably be better termed as disproportionate societal burden or something like that. Users balancing the cost of the habit to folks around them (even if it's not that particular user that's contributing to the problem -- part of the smoking related taxes is so that smokers that don't get complications and die help pay for the ones that do, after all. Ideologically, anyway...), even if it's secondary costs (lower lifespan, higher medical system strain, etc.).