Understanding from looking from the outside in... ?

I have proposed this question to myself; If one is not of a movement, sharing the identity of those who started it, can they be of the movement?

This thought only came to mind because, I'm trying to validate the argument that men can't be feminist, they can only be pro-feminist. Quoting from Wikipedia:

Feminism is a movement and a body of ideas developed by, for, and about women. Men can never fully know what it is like to be a woman. By calling themselves feminists, men could preempt and take over the feminist movement, thus stifling women's concerns and voices

Does this argument stand up? If one was to replace the word women with black in the above argument. Does it make sense? Only black people can be part of a black movement for non-black can't fully understand what it is like to black. So in turn, non-blacks can be pro-black movement but of the black movement. But if I remember my history correctly, there were black movement organizations from the 60's that had white members. And if there members of an organizations where core belief was in the black movement, don't they, the white members, by extension part of the movement. Wouldn't that give them the right to call themselves as part of the movement? So again.. where those members only pro-black movement or part of the black movement?

Race like gender is a charged subject. That exercise did not clear the matter for me.

What about he question, can a French national could have been an American Revolutionist? Can only Americans be American Revolutionist? In this matter, for me, the answer is clear. Yes, only Americans can be American Revolutionist. I'm not sure everyone would agree with me. And does this port well to men being feminist or not?