In my interpretation the judge is saying
"the need to deceive - wanting sexual experiences with heterosexual males - and the only way to achieve that being by deceit - is a usual ( removed double negative ) feature in sexual assault cases"
or
"what you did has an identifiable feature commonly found in sexual assaults"
I don't think the Judge is making excuses. I think he is justifying his judgement that it is sexual assault, and the prison sentence he gave.