Yes, all of us have ancestors who raped and pillaged, and were also the victims of it.
But what we are talking about is the intentional portrayal of some peoples as being more predisposed to doing this, in order to promote an image of those people as sub-human monsters deserving of death. (Probably either to harden their own people for the coming battle, or to identify a common enemy for political reasons, or both.)
I'm sure...literally 100.0% sure...that in Alfred the Great's era the Danish invaders were portrayed as especially likely to rape, even though in reality the A-S were just as likely to do it. Why am I sure? Because that image of vikings has persisted for 1,000 years. The difference (to the A-S) was, of course, that they were merely raping sub-human Danish animals, so it wasn't as bad.
So, yes, rape between enemy peoples has been common throughout history. But here's the question, that I'm only asking you to think about, not answer: how often do you envision Half-elves as being the product of rape, versus Half-orcs? If it's not approximately equal, then you have fallen for a variant of racist propaganda that exactly mirrors the propaganda used in the real world, historically and present day, to dehumanize others.