Would you quit?

Okay, so this may be in the wrong group (I can move it.) I need some advice.

I work as a secretary/assistant at a small family owned home services store. (Flooring, cabinets, dry wall, etc..)

We hire sub-contractors for the installation process. Well, I was in the back warehouse and listening to one of the carpet sub-contractors joking about how he raped a women. I tried to stay out of sight to listen in and see if it was true/needing of reporting. I didn’t hear much more because our male employees told him he was seriously screwed up and needed to not talk like that.

I went to the owner and told him about the situation. The owner agreed that it’s messed up, said he would speak with him to “make sure he doesn’t talk that way around me” and assured me he passed a background check before getting hired. But the owner doesn’t seem like it’s a big deal, and is treating it like a “boys will be boys” situation. As much as I wanted to, I didn’t ask him to no longer be used for installations as it’s not my place, but it seems like my boss as no intention of removing him. I’m so disgusted and angry. Would you quit? Am I wrong for thinking he shouldn’t be able to take out more jobs with the company?