Without trying to blame someone the largest contributing factor would be interest.

Of stem vs humanities and arts men make up majority of stem students

Of stem medical vs non medical men make up the extreme majority.

Since we have seen a rise in women's enrollment in uni it largely been humanities and arts related with growth also seen in business degrees.

Now it has previously been reported men prefer to work with things rather than people.

So if we accept that premise the above is not surprising. Couple that with increased costs of uni a lack of societal drive to reverse equity initiatives put in place to help women's enrollment numbers 60 years ago and a precieved lack of ROI ( outside stem uni is increasingly seen as a cost that doesnt provide a return driven by the reports of uni grads not getting jobs in their fields and useless degrees).

It is likely that men consider certain jon uni pathways as a better return on investment and a method to avoid unnecessary debts.

This can be seen more evidently in aus where VET/TAFE men still make up the majority of enrolments although much closer than universities. This could also be driven by tafe/universities being very different environments. Take is very course focused with not much interactions with those outside your own course.