Okay:
1. The young lady told the young man that, "You're a man." The truth is an absolute, unassailable defense. So, have the young man drop trow and the young lady will be exonerated. Case closed.
2. What exactly is the Washington Interscholastic Activities Association (WIAA) going to do to "discipline" this young lady for speaking the truth ... kick her off the team? They certainly cannot fine her or kick her out of school - because then her parents would have a golden opportunity to sue the WIAA into financial oblivion. Her parents might have a dandy case if they try to kick her off the basketball team ... especially if the feds get involved. If I was this young lady's father, I'd tell her, the next time she sees this young man, just say to him, "Hi, fella."
3. And finally, saying "you're a man" to a man constitutes "bullying, harassment, and intimidation"? WOOF ... what kind of pussified snowflake is this guy, eh?! Heck, he's not even strong enough to play basketball against teenage girls. Maybe the WIAA should find him a kindergarten basketball league to play in?