It’s not like they chose this situation either.
Would she complain this much if one of them had an infant on their lap? A dog? Body odor? A urinary tract infection?
When we fly, we don’t choose our company. All kinds of difficult things happen. Such is travel with other human beings. We can either resent others for existing in imperfect human bodies, or accept that we’re not so perfect either.
Cruelty is not such a great quality to sit next to either.