The only two reasons his phone was so heavily redacted could be a) he’s making up the crime and the phone proves it or b) he’s into something else illegal (think child porn).
Maybe both!
There is an infinity of reasons to avoid handing over the phone.
He could be protecting a bi-sexual lover who does not want his wife to know of the affair.
There could be many other posibilities. He might want to cover up a donation to President Trump, for example.
Maybe he used the word "Indian" when it was not politically correct.
The preponderance of the evidence agrees with your interpretation.
There's a 3rd possibility for why he redacted the phone records. The assault may have been a gay lovers quarrel, and he's trying to hide the identity of his attacker.
I immediately thought child porn myself. Great minds and all that!