Not the person you were talking to, but to me this just feels like a MASSIVE straw man. If you can show that some company prefers men and actually discriminates against women, I think most people would agree with taking action against this. Unfortunately, you are very far from being able to show such a thing AFAICS. Instead it seems you are working backwards and inferring that there must be some discrimination because the outcomes are so skewed.

For large parts of my life I've seen massive and explicit discrimination against men. In junior high/high school various programs intended to increase interest in tech enforced a quota on 50% girls. Of course, this quota was never written down in public anywhere, I just accidentally overheard the organizers talking about this. Then at university I had male friends who wanted to help out on a similar program, and apparently their applications were "lost". Then the next year the organizers added text in small print somewhere that they were going to enforce a quota on the genders. Similarly, I've heard professors comment on hiring decisions with saying that if they don't hire a woman, then they've basically failed.

Again, at work I very often hear similar things when people talk about hiring in both private and even more in public sector, "Wouldn't it be very nice if we hired a woman", "You know it will look very good if had a few more women on the team", bla bla bla.

I can't say I've ever heard anything remotely similar to this which is negative to women. Maybe I'm wrong or biased here, idk. Maybe this discrimination occurs in different places/positions in the organizations to where I am at. I'm trying to keep an open mind about this, but nothing really comes to mind.

I think there are two things which concerns me. Firstly, there is the difference between how explicit and clear the discrimination against men are when you are "backstage". From this side it is completely clear and there is no real attempt to hide it. But from the side of the person applying for the job/position/program, it really isn't very visible at all in most cases. If you are lucky there is some fine print somewhere. From my experience, like I write above, the discrimination against men/whatever is extremely frequent and pervasive in today's society, but of course, I just have my own observations and maybe it's different in other companies, etc.

Secondly, I feel the proponents of discrimination against men never point to anything remotely specific. It's always just "oh, there isn't enough women in tech", there is some "glass ceiling" stopping women, there are "hidden structures acting against women", etc. And at some point this starts to get ridiculous, like I've pointed out above, for more or less my whole life I've seen massive and completely open discrimination against men, and now I'm supposed to believe in some "invisible structure" which is acting against women all over the place?

Let me just finish by saying that I don't really claim to know why the world works the way it does, or why things are the way they are. And I don't think one should pay too much attention to all of these biology based explanations for why there are fewer women than men in tech. To me they are more just like "this could be one possible explanation for the phenomena as well". The main take away from them should, in my opinion at least, be that we don't understand this area very well. Unfortunately, I think people who propose biology based explanations often pushes these theories like we know they are true and that this is the explanation. I have not looked at the studies they refer to in any detail, but I have a hard time believing this is the case.