It doesn't matter what his intent was (although it did blatantly contain a sexual threat), his words were gross and inappropriate. If he doesn't know that this is being offensive, that's his issue, not everyone else's. We live in a culture where girls as young as 8 or 9 are routinely subject to this sort of treatment, often from grown men - and it continues throughout life. Pretending this an anomaly that we can't actually truly understand is frankly, being a rape culture apologist. Do better and stop being a part of the problem. You know why women are so mad at men — for this kind of clueless bullshit response that normalizes their marginalization, objectification, and pervasive lived experiences.