lola, positive discrimination is illegal in the UK, although I am aware that there are programmes like affirmative action in the US. Positive action (e.g. a statement saying "we encourage disabled people to apply because they are underrepresented in our organisation," is something different because the decision in the end is still "open."
The whole reason why there is a need for positive action is to level what is a very uneven playing field. Gender discrimination is institutionalised. It's so much a part of the "fabric" of our lives, political systems, businesses, public institutions, etc., that it's rarely questioned. Men, particularly those holding other privileges say based on class, ethnicity, education, sexuality, etc., are automatically advantaged by the set up.
Your last sentence is really off, imho. Are you trying to say that feminists should not be allowed to discuss issues here? Frankly speaking, if you don't like it, no one is forcing you to read it. Don't let the screen door hit your behind on the way out and all that . . .