It actually is.
I'm not sure if you are aware or not, but court is an adveseral system.
For him to put forwad his case he will have to go into the witness stand. As such the defence will have the opportunity to cross examine him and one of the things they will is to try and bring his character and motivation into question.
If you think otherwise, you are fooling yourself .
Q. Why did you choose not to go to the police?
Q. Why did you choose not to lodge a complaint with the Geelong Football Club?
Q. I put it to you Mr X, that the reason you didn't do either of them is because it never happened.
Q. I put it to you that you are only bringing this up now as you wish to make money from the Geelong Football club and that's why you never reported this alleged assault to either the police or the Football club.
This is absolutely the line of questioning that will be put to him. This would be on the tame end of it. Lawyers can be brutal.
And there’s fair & reasonable responses that any judge would accept, such as sexual abuse historically not being acted upon in reports.