It's not about health or tobacco. It's typical political crap.
There's three groups of people... anti-tobacco, indifferent, pro-tobacco. Indifferent people don't care either way, so politicians don't care about them. Anti-tobacco people vastly outnumber pro-tobacco.
Marijuana is an entirely separate thing from tobacco. More people are pro-legalization than there are anti-legalization.
This is all just politicians looking for easy, low-hanging fruit to give "the people" an easy "win" so they won't have to do real work to fix real problems, because there's no money or power in that. It's about keeping the populous complacent so that it doesn't rise up and revolt. Makes them look like they did something. Giving people what they are already doing on their own is way easier than trying to fix crumbling infrastructure, for example.
Most of them could probably give a shit less one way or the other on anything as long as it doesn't cut into their tee-time.