I never said all men or all women, but the reason you remember the exceptions is because they are exceptions to the rule. MOST women do not allow themselves to be 'friend-zoned' THAT is a fact. MOST men, at some point in their lives find themselves in this situation because they let it happen. Heck, this even happened to me when I was in high school... granted it didn't last very long, a few months, but it did happen, and it was pathetic. Usually it happens early on, but we all snap out of it, and if we have any amount of self awareness will not let it happen again.
This happens to men even when they do not have low self-esteem, which on the rare occasion it happens with women, it is typically the cause. This happens to men because of biology, massive ego, and the mythology that anything can be 'fixed' with effort. Any man that is completely honest with themselves will admit this happened to them at some point in their lives.