Since you're accusing human rights watch from inaccurately reporting this ... can you provide a citation for your new fact that there was a second offence ? Or are you perhaps claiming that while the rape was an offence of the rapists, getting raped was a separate offence by the victim ?
I would also like to point out that punishing rape victims is part of islamic rules:
e.g. "if a man comes upon a man, then they are both adulterers," "If a woman comes upon a woman, they are both Adulteresses," "When a man mounts another man, the throne of God shakes," and "Kill the one that is doing it and also kill the one that it is being done to." (Abu Dawud 4462 and al-Tirmidhi 1456)
Google it to find more references than you could ever need to be satisfied. And yes, this is about gay sex, but is widely interpreted to include gay rape. Getting raped by someone of the same sex as you is punishable by death according to sharia. Are you seriously disputing this ?
And just so we're clear. We're talking about this Saudi Arabia:
https://en.wikipedia.org/wiki/2002_Mecca_girls%27_school_fir...
Where the "religious police" beat up firefighters and sent rescued girls BACK INTO THEIR BURNING DORMATORIES because of the mingling laws ... at least 15 did not survive.