Because college is where women are driven out of computer science, by behavior from professors and peers. If you want to talk about fields where men are driven out (and they do exist: primary school teaching and nursing come to mind) go to a thread about those. But either way, derailing this discussion doesn't help.
The men interviewed for the paper disagreed that discrimination, social barriers, stereotypes, or other forms of injustice play a role. ("I don’t feel that there is any injustice… men who want to teach, are able to. It’s not like we’re being held down.")
It also points out that a greater number of men than women choose to go into primary education during college, which is the opposite of what we'd expect if they were being driven out by professors and peers.
Because college is where women are driven out of computer science, by behavior from professors and peers. If you want to talk about fields where men are driven out (and they do exist: primary school teaching and nursing come to mind) go to a thread about those. But either way, derailing this discussion doesn't help.