none2 > someone can ban others from reading a text
a good point. All those halachik sources, as far as I know, talk about desirability of _teaching_ girls, not about them learning themselves. Of course, it was the time of Torah shebealpe. Still, Beruriah went to hundreds of teachers – on her own – and seemingly none of them stopped her from attending the class.
Note that Rabban Gamliel used to stop undeserving students from entering his yeshiva, so the concept of closing the doors was there.
Focus on teaching may be the source for the opinion (that sounds reasonable to me) that learning should be only for those who want to.
Note that the same is desirable for men also. Avoda Zara somewhere 16 mentions a student who wanted to do Mishlei but the teacher started Tehilim. When he interpreted a verse in Tehilim that the student should learn what he enjoys, the student said – you just gave us permission to go to Mishlei!