He (assuming is a he) probably refers to the fact of her being stoned and drunk.
Indeed if she is drunk and/or stoned or anyway in such a state that she is unable to give her fully understanding consent, in some jurisdictions that is considered "sexual assault", or another formulation that is considered similar to rape.
Though that is based not only on the state, but on the fact the victim feels as a victim the day after (and files a complaint, to have the criminal case opened, in general, this type of crime is investigated based on the complaint of the victim, though in some cases and jurisdictions, there can be exceptions).
As far as I recall, Myriam did not feel raped, at worst (depending from the choice of the player, if I remember well), she felt she had let the thing go too far and could have stopped it but didn't, and effectively she did not blame the boys, because the boys did not try to secude her, and as far as I recall the boys did not try to get her drunk with the purpose of having sex, did not pretend not to have sexual interest, and did not give her even the drink trying to hide the quantity.
But despite the fact that when I had in real life situation with drunk clearly showing or saying what they wanted, I did not "do it" (or do them, if you prefer a more brutal variant ;-)), I would not call those boys rapists, but opinions can (luckily
) differ, and in his opinion evidently they are rapist.