This thread reminds me of Pulp's Common People.
Even if someone with privilege actually (not theoretically, but in rl) puts themselves into an under-privileged position, there are 2 reasons that mean they won't entirely 'get it'.
- All those previous years of privilege will help them in many ways (attitude, health, education)
- They will know that there is an 'out'.
And that second point is key - people whose entire lives have been immersed in lack of privilege/oppression, often do not even know that there are ways to escape/change etc. They are probably aware that other people have a different kind of existence, but they have no concept of that life being available to them. It takes a huge mental leap to see that they can change things, let alone know how to change them, and then to have the stamina to enact that change in the face of opposition.
Just one small example - if a man poses as a woman and then discovers that in work meetings their opinions aren't listened to as much, they get to see and have some insight into what it is like to have a silent voice. That still doesn't mean that they have any idea of what it is like to grow up in a world where their voice always has been and always will be heard less. That they have lived a life where they are talked over, ignored, shouted down, not called on in class, have their right answer ignored until a male says the same thing. That if they raise their voice they are called shrill, if they speak normally they are ignored, if they get frustrated they're called hormonal.
A man facing that situation will have the pre-knowledge that his opinions should be listened to, and the knowledge that he could come out of disguise and be listened to again. A woman would not have either of those assurances, and is likely to believe that her voice is less worthy. Even if intellectually she knows she should be an equal, she may well still believe that her voice isn't as worthy of being listened to. So. As well as experiencing the oppression, she is internally struggling with cognitive dissonance.
Which is why it is condescending for men to say 'I know how you feel' - because they don't. They can't. It's not their fault, but that doesn't mean that they do genuinely understand how it feels, what that life experience is. And they have to accept that. No matter how much they sympathise, they cannot replace an entire lifetime of experience with a few days/weeks/months of experience.
That is why, within the area of feminist discussion, they need to be listening to the best of their ability.