Myself, at 6'3" and weighing 10 st, or about 62kgs admit to 8 1/2", I think that it's more a matter of scale and proportion, the dick isn't that much bigger than others (heavier built) guys but it LOOKS so much more,

Imagine, you put a pea on an ironing board, you instantly see the pea, put the same pea on an eggbox and the peas less obvious....it's the same with dick!

Just my two pennies worth.