Many gym rats who want to be human bisons (e.g. they train the biceps and chest and ignore legs) do not have pullups (or squats) featuring anywhere in there routine. I have not looked at your journal g8r80, for example but what do you do for vertical pull? Any pullups? Even without looking I would guess not.
People believe myths that they are too heavy to do pullups/chinups and that they should stick to the assisted pullup machine for life. Look at the stronglifts website and tell me if that is not a 310 lbs individual doing 21 pullups.
Compare the size of the lats and the size of the biceps, you have people doing 21 different types of bicep curls and zero/nothing for the lats - is that proportionate?
There are huge people who can do many pullups, which is even more impressive, but that doesn't mean that it's normal. 20 pullups is pretty rare (strict pullups, that is), nomatter how you twist and turn it.