Why do Chinese women (men) hold hands?

Women are not to go about unescorted at night:

I was informed of this tidbit and the next one shortly after arriving on campus, much to my dismay. Chinese life 'happens' at night; that is when the street vendors hawk their wares, when the people hit the streets and parade around, when housewives bring out the boomboxes and dance in the square. Apparently my former lone nighttime wanderings were tolerated because I was a foreigner and a tourist, but as a member of the teaching institution where I work, I am expected to set a good example and do nothing to deny/decry Chinese culture. It would not be appropriate for my female students (who do go out in pairs or gaggles) to see their esteemed professor flout Chinese culture by stepping out alone. Unless I have an escort, I am compelled by this social edict to spend evenings in my apartment.