It's not as rare as you may think. It's true that TIMs generally get into a lot more trouble (one school shooting not withstanding). But I've heard a couple cases of TIFs committing rape by deception before. At least one was also in the UK, which sadly may mean most other countries don't consider it a crime. Rape by deception exists in US states for instance, but generally it only applies to impersonating the victim's romantic partner, not simply lying about your own identity.

Edit: As someone else noted, the perpetrator in this case may not identify as trans at all. If not, I wouldn't say that makes the crime worse, but it does seem to cut off an excuse. (e.g. "I wasn't trying to deceive anyone, I just get so dysphoric when people see me as a girl...")