Nah they're just lying, they want those of us out here who're never going to actually see them in real life to think of them as "big men" because in reality they have tiny penises.
Being 7ft 3 myself I would know nothing about that.
The average height here seems to be freakishly high, with over 50% saying that they are 6ft and above. I always though that at 6ft I was reasonably tall, so I get the feeling that one or two members may be telling porkies.