I am aware of that.
And that is EXACTLY the annyong thing ... "balls" as in "testicels" refer to a part of the male reproductive system and primary sexual characteristics of a human male.
So why apply it to a woman?
Because if a woman shows strength of spirit, success, self-confidence, whatever ... she is no longer considered to be a "real" woman by male society. She is a thread and an intruder.
Don't get me wrong, dear ... I appreciate the compliment because I know you're not that kind of guy, I just don't like that particular expression.
But this thread is not the appropriate place for a discussion like that.