Earlier quoted context omitted.
“Whats utterly crap is the way large people are hounded into expensive seats on specious "it's your lifestyle" reason” I disagree. Airplane tickets are expensive and the seats are already extremely cramped. If you don’t adequately fit in your seat, why should the person at your side have to suffer?
Their point is that the seats are not sized to 'common people'. At the very least I'd say it's likely a not-small portion of American adults are larger than common airline seats want them to be.
The laws of physics don't care about people's feelings.