Interesting, and legitimate sources. I don't disagree that there's a problem here, but there are far too many nuances to pick apart, so I'll go about this more obliquely.
First: the way you approached this engagement started with a claim that most feminism has a "tenuous grasp on reality". Claiming that the reasonable feminists are a tiny minority is a good way to suggest that every claim the person you're responding to is probably wrong, in your view. In other words, saying "often (not always!)" isn't enough; that doesn't introduce nuance. That introduces antagonism. The best suggestion I can give is to demonstrate a knowledge of feminism that you support while explaining why this particular school of thought is wrong.
Second: there is a systemic marginalization of women. Moreover, this is demonstrable by a lack of one-to-one gender representation. You start to address the issue reasonably in your complaint, but you revert back to dismissal rather than recognizing that people are working on control mechanisms. Yes, affirmative action style programs are a blunt instrument, but that's something to "fight on the merits of the argument". I can make arguments both for and against it, and I rather expect you to be able to as well.
If random chance is determining the results of something, a 50/50 gender split is a reasonable expectation across a large enough sample. If that 50/50 split isn't present, then that suggests there's a significant effect besides random chance. We can claim that's a biological thing, or we can claim it's a cultural thing, but it's systemic either way, and this wouldn't be the first thing we decided culture ought to trump biology on anyways. (lol typing on keyboards at midnight)
I'm pretty sure you knew this, but it's unclear based on what you've said so far.
Third: It's worth pointing out that a lot of the people you're going to come across online are going to be American, which means our views are colored by the fact that feminism is losing as much as it's winning in this country. We have prominent public officials making unquestionably misogynistic statements, and the best we have to show for it is that a few of them were voted out of office.
Maybe feminism has achieved an unassailable victory in Canada. I don't know; I don't live there. But it hasn't achieved it everywhere else, and certainly not in America. I notice that I rarely see such an announcement for a program or conference in Canada. I see them for the US, for the UK, for India. These places are not bastions of feminism.
Fourth: There are some notable bits in your links demonstrating a problem. It's this: some men's rights activists are making the same mistake as the worst of feminists: they're tearing down all women in the name of being supportive. Claims like saying rapes are over-reported or slut-shaming with a public poster are petty and damaging. Creating a safe space for men who are abused or oppressed is fine, but leveraging that in order to push women down? That's not okay. It wasn't okay when women did it, and it's not okay when men do it.
The inevitable consequence? Exactly what you're complaining about: feminists who recognize a threat and respond to it. Which causes another round of men who are angry about being oppressed. Which results in an escalation of feminists yelling them down. And the worst of it is that they are both right. If you want to fight against this kind of feminism, then you need to temper that with the acknowledgement that what some men's rights groups are doing is in fact wrong.
Fifth: You know why people respond with "yeah, that's cool"? Because they're sexist. Because they unconsciously believe that men are stronger and should be able to tough it out. Because they believe women need to be protected. Because, you know, we still look down on women. Empowered women are still considered an exceptional case, rather than a natural fact. And that's probably not going to change in our lifetime. It's the kind of thing that needs to bleed out over generations.
Sixth: I believe I've met an example of what you're talking about, online, and if she's representative at all, this becomes a component in a larger theory. I am of the belief that people who bully, who oppress, are people who have taken it from others and are effectively passing it on, knowingly or not. This woman yelled at me about how rare decent men were, for instance. It put me into a months-long fugue, but I'm not the kind of person who has the luxury of support groups.
What it sounds to me is that you're seeing the tail-end of a cycle: you noticed a chicken hatch from an egg, so of course chickens come from eggs; you're just not viscerally seeing eggs coming from chickens.
Seventh, and finally last: This, "I find it disconcerting, and feel a need to argue against" is exactly what people feel when they read what you write. As previously noted, I don't really care about feminism. (...and checking back, that was part of the comment I scrapped. Bah.) But I do feel I have a strong enough grasp on the fundamentals that I can explain it usefully in argument.
When you make this kind of "men need advocates too" claim, that sets off warning bells. After I wrote all the above, I hope it's clear why. You caught me on a day I was feeling good. Other times, I'm more interested in handing out a beat-down and would not have stopped to ask for clarification.