Question about the word female

What is it about the use of the word female?  Why is it being used more?  What the hell is this all about?  Seriously.  Look, I've seen people, men and women , write "men and females".  For me, using male and female to refer to people is like you are refering to them like animals.  A female dog, for instance, because you don't want to say bitch.  And female gets tossed around far more than male.  What the hell?