This might be a surprise to you but that's because they are, and always will be, their birth sex, and male and female cognition are fundamentally different.
That's true to some extent, but I think what most of us here find so amusing about pooners (and transwomen, conversely) is that they do even
worse than you'd expect, and worse than the average person, despite claiming to be blessed with supernatural cross-sex souls.
Like, if you can imagine some unlikely hypothetical situation where a female person was compelled to do her best to pretend to be a man for a week, it seems to me that the average woman reading this thread, or even the average woman on the street, would do a better job than the average pooner. Yes, they'd be unlikely to actually fool anyone and they would still look ridiculous, but you could still expect
better. For example, most women would probably at least attempt to put on a good "How do you do, fellow men?" act rather than hiding in their room crying at the thought of interacting with males like most pooners do.
That's what makes it so funny, that the average soccer mom or Catholic grandmother knows more about the male experience than most FtMs, because those women have actually interacted with a variety of men during their lives, whereas for pooners "men" seems to be a fundamentally an imaginary category that they have picked up from fanfiction and animu comics.