If you ever feel like saying to a woman, "not all men are like that!", I suggest you reflect on the fact that women, being well accustomed to resisting a world that insists all women be part of a monolithic bloc of pink, perfumed femininity in an attempt to express our own selves as individual human beings, we really, really, know that already.
It would be far more productive for you to instead say, in response to whatever it is you feel the driving need to distance yourself as a man from, "what a [sexist] asshole!" and actually criticize the behavior of another man instead of being so damned namby-pamby that you can't stand up to another man. Until you do, you condone men who are "like that", you demand we consume valuable time and attention soothing your ego saying "yes, yes, we know", and, in the process, you make yourself precious little better than being "like that" yourself.
HT: The Pursuit of Harpyness (awesome blog title), "Don't Tell Us."