Maybe you recall that in many cultures in the world, menstruation is regarded as a sign of ritual impurity. So using it sround a woman is somewhat like using the term "ho".
Don't matter what you think. Just don't use the term around a Middle-class English lady. She won't bop you, but she will give you a very dirty look.
Oh please, give me a break. How many Brits are you around on a daily basis? I am living in Bangkok and associate with Brits daily, including some good friends. I have yet to meet a Brit, or Aussie or Kiwi, who is half as touchy-feely as the people posting on this thread.
Since you are obviously not aware, 'taking the piss' is a national pastime in the UK. The only people I have ever seen get angry over this are Americans. The Brits can dish it out, and take it, with the best of them.