Perhaps because you mostly read tech news sites, and not nursing news sites. This stuff (in both tech and nursing) rarely reaches the mainstream news sources, so people not involved in the industry generally are unaware of it.
Definitely it is well known that there is a shortage of men in nursing as well as in clinical psychology for example, and many in those industries think their industries would be better off with more men, and make efforts to change things. Some random links:
https://asunews.asu.edu/20121130_meninnursing
http://www.nytimes.com/2011/05/22/health/22therapists.html?p...
I have a background in psychology, so I know less about the nursing situation, but in psychology it's definitely a topic that comes up. Which is not surprising, the gender disparity is very large: When I was an undergrad, I was in a small minority, somewhere in 10-20%, and it can be an odd feeling.