You cannot make another person behave, think, or say anything in particular. When someone addresses you and you don't like it, you say you don't like it and then leave it alone; there is no right or wrong, fair or unfair about it when there is no arbitrator or way to enforce it. It is like if you go to a restaurant and the staff are rude and the food is bad; will you go again? No, you just don't go rather than start a vendetta against the restaurant, unless you have nothing better to do?

Sounds like the first guy enjoys engaging people negatively; you do not have to enjoy being so engaged; just don't be there for him to engage and he can't engage you; if you had ignored the original message, he could not have had any "fun".

With the second guy at the table, I do not understand why you found him a chair? If you don't want him there, you don't find him a chair!