because people have different fat storage patterns, sensetivities to insulin, estrogens, progestins....ect. I dont get belly fat bad at all, but get terrible love handles.....i put on fat like a girl and sometimes it helps us who do cardio and follow a good diet but hormones/chemicals in our bodies make it hard to loose fat in certain areas.
Not to mention, when you become overweight, your body makes NEW fat cells and when you loose the weight, you keep the extra fat cells....with more fat cells than before, its easier to put weight pack on and harder to keep it off. I have that in my handles.