These kinds of events literally exist because of things you yourself pointed out. Why should women be forced to potentially subject themselves to harassment? Why can't this theater host an event that ensures that they will not be ogled or harassed or abused or what have you? I'm sure the woman who was objectified by the band leader you now hate would have enjoyed not having to have that happen.
And two things:
1. It's more than just a few bad apples, and
2. People who use the bad apple analogy keep forgetting the rest of it: they spoil the bunch.
I agree society is far too lax when it comes to tolerating sexual harassment. I just don't think the solution is to create public "no men allowed" zones (to be clear, I don't think this lone movie theater is going to cause any sort of societal shift in that direction, I'm just speaking to the larger point). And I'm not sure how you can apply this logic to my example of the concert: are you suggesting it should have been a performance where only men could attend, so the woman couldn't have even been at risk for harassment in the venue? Or are you saying the victim would have enjoyed the opposite, where only women were allowed to see the concert (which also doesn't make sense, since the band itself was all male)?
Saying a few bad apples spoil it for the bunch is a really dangerous line of thought. You can see how that type of logic can easily be applied to justify things I'm sure you don't agree with. "Ethnicity X commits more crimes than ethnicity Y, therefore the two groups should be separated because the bad people in ethnicity X has spoiled it for everyone else in their demographic."
I'm a very strong proponent that people should be judged as an individual, held against the story told by their own actions and inner character, as opposed to being lumped in with the absolute worst of whatever group they belong to. I'm sure most people agree with that sentiment, but it seems weird to carve out some exception when it specifically comes to the separation of men and women.
A much more effective solution would be for venues (and society at large) to stop seeing harassment issues as minor deals that aren't worth clamping down on. It's hard to enforce these things for sure, especially when American was fine with electing a "grab her by the pussy" piece of shit, but that doesn't mean we should throw in the towel and take shortcuts. As far as the law of the land is concerned, my view is that no public business should be able to refuse service based on any demographic trait.
In my example of the concert I attended, if I were the venue owner I'd:
1. Blacklist the band for life (in this case, it would be
The Lord Weird Slough Feg)
2. Make sure the security guards know that if they see any harassment, the offender must be kicked out of the concert immediately; and
3. Have well-designed PSA materials posted throughout the building describing the venue's policy
I would encourage any and all businesses to adopt approaches like this, as opposed to a guilty until proven innocent mindset.
You were privy to just a few anecdotal examples like that heavy metal sexist live concert. How about you ask any woman who's gone to a predominantly male convention and ask if they've never been sexually harassed. How about you ask any woman you've ever met about how often they're sexually harassed out in the public. Any age, 10-70. Just so you know it isn't only a few bad apples, but quite the majority. Sexual harassment and assault statistics are depressingly high, even in western developed countries.
Sure if you want to get really technical, you can get people to agree women-only events have an element of discrimination. But then so what? Like if women go to a women-only event and you show up to them saying "btw this is a discriminatory event, that's all I wanted to say but I'm not like those actual sexists and am totally in support of feminism", how'd you think they would respond to that? Glad you pointed that out? Or weirded why you need to, were you instigating something? Women didn't make society how it is to the point where they need safe spaces. So don't put it on these events, put it on society where such a thing needs to exist so women can enjoy a public event in peace.
You're worried about being called a "white knight" by some sexist idiots, like really? It's like being bothered by Trumpers when they would call you a "cuck" or "libtards". You don't need approval from those kind of people. Just know how you enter a conversation, the first impression counts and if you bring up something that's considered negative, that's on your execution, not others who don't know everything about you to differentiate.
I want to respond to this section of your post first:
How about you ask any woman you've ever met about how often they're sexually harassed out in the public. Any age, 10-70. Just so you know it isn't only a few bad apples, but quite the majority. Sexual harassment and assault statistics are depressingly high, even in western developed countries.
Maybe my use of the phrase "a few bad apples" wasn't wise, because of how subjectively it quantifies things. I know the majority of women experience sexual harassment at some point in their lives, but that doesn't in turn mean that the majority of men are sexual harassers. Maybe over 50% of guys are, but I find that incredibly hard/too depressing to believe (I'm open to changing my views on this point though, if there is any data out there suggesting otherwise - though I'm not sure how something like that could be accurately quantified and measured).
For example, even if only 5% of men at comic con are harassers, that can easily contribute to the perception that most men in attendance are disgusting slimeballs. Obviously 5% is still way too high of a threshold to be acceptable, and an ideal society should have 0% harassment, but instead of taking the approach of "Let's just separate the men and women from these events to avoid potential harassment scenarios altogether," a better solution would be similar to what I proposed for the concert venue. Make the zero-tolerance harassment policy crystal clear, kick out anyone who does it, and implement lifetime bans.
I would never go and protest something like this movie screening. There are so many bigger fish to fry in society. Again, as I mentioned last night, I don't think the real-world ramifications of this women's-only event will cause any harm worth getting angry over. I'm just trying to argue that, on a philosophical level, this is a bad solution to a harmful problem.
As for accusations of white knighting, I didn't mean to imply that I give even the slightest time of day to what a brainwashed Trumper thinks. Instead, it's just another example of how two different groups of people can take the same action (speaking out against injustice) for wildly different reasons (actually being sexist and thinking women can't defend themselves vs. speaking up against wrongdoing no matter what the sex/race/orientation/etc. of the person being harassed is). It's very easy to always assume the worst about a person's motivation, but that's a dangerous and alienating assumption to make.