Calorie Burn

ITLBOK

So I've had some people say "that's it" when they ask how many calories I burn. Whether it be for a 5K run or a 45 min Workout. I explain that calories burn depends on many factors of each individual - sex- weight height etc.
On average a 5K run nets 300 calories and a 45 min work out nets 190-307 calories which for my height/ weight is my norm.
Why do I let naysayers get to me