But I thought it was impossible for other people's smoke to bother anyone or to cause an allergic reaction.
Well, we both know that's an ignorant statement. I may smoke, but I'm not unaware of the risks, nor is it my intention to inflict my habit on others.
Don't paint me with the same brush as those who claim smoking carries no risk. You just make yourself look ridiculous.
I'm annoyed by fat people, but I haven't sought (yet) to banish them from society.
BTW, allergic reactions require protein.
There is no protein in tobacco smoke.