Alcohol has negative social externalities just like cigarettes. People who drink often drive and make other bad decisions that don't just damage the drinker.

The negative social externality may not be "second hand drinking", but it exists nonetheless.

But you don't have to smoke and do something else to be harmful.

Sure you do. Smoke and walk around in public. Smoke and stand in the middle of the sidewalk. etc

The point is that these are not necessary. Someone is not harmed if you drink in the same room as them and do nothing else.

Not true they might drink too much and start complaining about me smoking.

"People who drink often drive" is a nonsensical statement. People lose their driver's licenses permanently for drinking and driving. People get high on cannabis and drive too. And people smoke cannabis outdoors, which smells worse than cigarettes if you ask me. So as far as public nuisance goes you get the worst of both worlds... except cannabis is the "cool" drug for younger generations, so people will bend over backwards to make excuses and berate you for criticizing it :)

Yes but alcohol is going have a far far bigger impact on their temperament and behaviour than even 100 cigarettes in a row.