Many foreign airlines have strict limits for cabin baggage. Americans aren’t used to this, they can pretty much drag anything onboard that is going to fit in an overhead bin as long as there’s still bin space available and certainly US airlines don’t weigh your rollaboard.
Whether Air France or Virgin Australia, airlines around the world take a different approach even for business class passengers. I do my best to avoid check-in counters when I’ve got heavy bags. If I can get a boarding pass online I will. But if I need to approach the counter, and they see my bag, they’re going to want to weigh it.