You forgot the quotations around victims, because it looks like there was no victim here, only """victims."""
If anyone is the victim here it's the teacher.
I'd certainly sing the same tune; highschoolers are no less logical than the average (young) adult who's 18-24. As long as both parties like it and it wasn't forced/pressured/etc, then who cares.
It'd be different if she threatened the student with grade punishments, but if the student isn't coerced it's none of anyone else's fucking business. Sure, it may seem odd or weird, but so does two men fucking if you aren't homosexual. That doesn't make it wrong though. If that's what they want to do that's their deal and their deal alone.