The problem with this is that we’re using our understanding of consent, mixed with magical powers.
One could argue it’s similar to consent when under influence of alcohol or drugs.
But can we classify Love Potions in that way? And if this was in muggle court, no way would it be considered rape, as the potion doesn’t exist in their minds.
And in Wizard court, I’d believe the act of USING the potion is what they’d focus on, not the activities they hade while he was under its effects. All in all, legally, if it was rape or not would probably never be discussed in muggle or Wizard court.
But this is just my idea