Setting that weight limit would impact on a high number of sports people (tall and muscular)
No-one is proposing a weight limit, nor is anyone proposing to charge passengers extra based on their weight. This is about safety - making sure you have the right amount of fuel on board.
Feel like there are a lot of insensitive and judgemental comments on this (unless people are qualified aero nautical engineers) for non experts on aviation and weight issues on a plane
It is actually fairly basic physics. You don't need to be an expert in aerodynamics to understand. But I do have a friend who teaches commercial pilots who confirms what I'm saying, if you want my qualifications. I also have A-level physics.
The more weight an aeroplane is carrying, the more fuel it will need to burn and the more runway it will use getting airborne. At the moment airlines use estimated weights for passengers and hand luggage. That may mean they have a smaller safety margin than intended or waste fuel by carrying more than they need (which is bad for the environment). Knowing the actual weight of passengers and hand luggage would allow the captain to make sure he had the right amount of fuel on board to give the required safety margin.