Those who say it are wrong. But you are wrong too. Because you give professional sportsmen pictures as an example that their hair loss persists even though they are doing sports. Do you know that this kind of 'sport' is actually a killing machine for health and that they have to do it for 9-10...
I am not the doctor, so for me it is hard to say. Visually your scalp looks fine, but if the dermatologists finds nothing, maybe you need to visit a family doctor once gains and ask for hormone tests to be done.