Ah, kids. I wrote about this urban legend blogospheric eons ago. As a commenter pointed out here then, it's possible it has its origins in Marilyn Frye's essay, Oppression:
"The door-opening pretends to be a helpful service, but the helpfulness is false. This can be seen by noting that it will be done whether or not it makes any practical sense... The gallant gestures have no practical meaning. Their meaning is symbolic. The door-opening and similar services provided are services which really are needed by people who are for one reason or another incapacitated – unwell, burdened with parcels, etc. So the message is that women are incapable... The message of the false helpfulness of male gallantry is female dependence, the invisibility or insignificance of women, and contempt for women."
I took a handful of women's studies courses back in the early '80s [at the first University to offer a major in women's studies, btw] and I'd never heard of Frye or this essay until last January. Maybe I ditched and went surfing the day it was covered. Is it widely taught?
Or, more to the point, has there ever been an angry mob of protesting feminists who refuse to have men open doors for them? Does anyone have the time to register the gender of someone opening the door for them? Or is this simply yet another instance of taking the opinions and/ or actions of the fringe and attributing them to a larger group in an effort to render the larger group or cause perjorative in the mainstream?