If it only affected the user, sure, but the reality of it is that the smoke contaminates everything around it.

I was in my 20's when I realised it's not normal to mop your walls every year, also made the connection that moving out reduced my migraines. I did not realise just how much I stank everywhere I went thanks to my mum's smoking, and coming back off holiday from smoke free relatives I felt my throat and eyes burn as I was settling back in at home.

My neighbours a few doors down sometimes smoke in the garden when the weather is nice, so I have to shut all my windows and retreat indoors if I want to keep breathing freely.

It's a lot better than it used to be, but it still restricts my comfort and quality of life if someone nearby decides they have the individual right to smoke.