Here's what's bothering me, again:
If she had required all the band members to be under five feet tall, people would have been like, "Um, that's weird." and had a good laugh.
Yeah, and that's the same reaction I had to the announcement that she wanted all men. Rather different from your violent reaction.
If she had required that all band members be white, most people would have strongly disapproved.
Heh, because I'm sure there are a ton of non-white metal musicians in northern europe waiting to try out for her band! That aside, I wouldn't "approve" of this any more than I approve of her desire to have all men in her band. But I'm apparently able to realize it's not my job to approve or disapprove of what characteristics someone wants in a band she is forming.
The attitude here to her requirement that they all be male, however, is a rather belligerent "It's her band!",
It's not belligerent. You're simply interpreting it that way because it's apparently not what you want to hear. It's probably become more forceful as the thread has progressed because you keep repeating the same thing.
which would not have been the response had I posted a thread about any other unusual requirement.
I can't speak for what anyone else's response would have been, but it certainly would have been my response. If she only wanted, say, green-skinned hermaphrodites in her band, well, I wouldn't select band members based on those criteria if I were forming a band... but if I were the one forming a band, then it would actually be my concern. You seem to think it's your responsibility to pass judgement on her selection criteria, then dub her and everyone else who doesn't get as lathered up as you "sexist". Whereas I simply understand that it is and should be her prerogative to select such band members as she sees fit, even if I think her criteria are weird.
And I think that's significant.
Think again.
It tells me that sexism is okay,
It might also tell you that pigs can fly, but that doesn't make it any more accurate.
and that many will vigorously defend it,
No one is vigorously defending anything. The basic error you are making here is that you think people pointing out her obvious natural right to use whatever selection criteria she wants, means they are somehow condoning those selection criteria. The only "vigorous" thing here is my amazement at how you are still unable to grasp this basic fact.
whereas racism or a requirement that the entire band be proficient in polka would not be, even though it's her band.
This is irrelevant. She is free to have *whatever selection criteria she wants*. You've said that her selection criteria are "not ok". Let me ask you, who exactly are you to decide what is "ok"? You can decide what's ok for you, but what makes you think it's your prerogative to decide what's ok for her? You're trying to play it both ways in this thread, making statements like "yeah it's her band, but it's not ok". Well, which is it? As has been noted, the band members have already been selected at this point. Unless you have the power to forcibly create an arbitrary "council of inter-band egalitarianism" or something, you can keep banging your head against the wall in this thread, and it's not going to change anything.
Now, this still leaves us with the basic question of why she wanted only men in her band to begin with. Unfortunately, none of your histrionics or blanket labeling of everyone as sexist have done anything to shed any light on this. If you're actually interested in this, why not make some actual attempt to contact her or her management and ask? Because otherwise, you're just proving the comment that several have made that this thread is simply idiotic.