It tells them that inclusivity is against their interests. Boys growing up where they are explicitly barred from opportunities due to their gender are probably not going to be very willing to accommodate women in the future. Also things like this has shown to not move the needle, so all you accomplish is drive the wedge between genders even further down.
> I think how Guido wants to spend his time is up to Guido.
And we are allowed to criticize him for it.
I think that interpretation grossly over-values Guido's mentorship contributions.
Note that this isn't a radical conspiracy - it's already happened in some areas. There are a lot of colleges with special inclusion resources for women, even though women are significantly overrepresented in the modern university system.
I have participated in events for gifted children, including teaching python. One such child already had before they came to the event written up the whole game design, painted the different rooms and enemies, created most of the game logic and now needed help with hit detection in pygames. Hit detection is quite a bit beyond the tutorial part of pygames, but in the end we mostly accomplished the goal and they left quite happy. Did I care about their gender or even asked about it? Of course not. Here was a person who needed my help.
Maybe no immedient harm would have happened if I had rejected that child based on their gender or treated them as part of a homogenic group with unchangeable inherent traits. There is always other people, other resources, and they clearly demonstrated the ability to self learn. But what kind of person would I be if I did that?
No. They were a boy though. I'll tell you why I'm saying that with confidence: because we know men are most of the Python userbase, and they're more comfortable approaching other Pythonistas for help because they're other men. Argument from statistical probability.
That's specifically the issue Guido is seeking to address, and he's not going to do it successfully by not caring about gender. Not caring about gender tends to get us more of the status quo, not something approaching more inclusiveness.
If the kid was a girl, good for her and I commend her forwardness and bravery. We know most women aren't interested in putting themselves in that position because it's uncomfortable for them (any more than most men are interested in stepping into a knitting circle to learn more from a group of women). And if Python as a community is to grow the pie, that situation needs to change. So that it's not just you who doesn't need to care about the gender of the student; it's the student who doesn't need to care about the gender of the teacher.
I think how Guido wants to spend his time is up to Guido.