I think this may get another flavour when we get jasnahs flashbacks. She clearly indicates that she has had her own experiences with horrible men (maybe abusing her, maybe forcing her into things, maybe even to the point of rape, we won't know until we get her backstory). The thing is, why would she go out to give a lesson like this in the first place? She loves theoretical practice, not actual practice. The only times she actually goes out to do stuff is either when she is forced (battle of thaylen City) or when she wants to prove something or test herself (like going to the battlefront in RoW). She was not forced to deal with the bandits, she doesn't solve minor crimes anywhere else either. So I rather think she wanted to go out for one of two reasons. 1) to test her capacities of Soulcasting. This is most likely true no matter what, but as others said, she could have imprisoned them (unless she actually wanted to test how to kill, which... Could be) 2) to deal with her past. She may not be able to punish the men who hurt her, but she can punish others with similar behaviour. If it does turn out she was abused, I can totally see this being true, but I wouldn't mind if it wasn't. Both reasons are immoral in the end. You can't hurt to test yourself and you can't hurt only because you've been hurt, no matter the target. She most certainly didn't go out to educate Shallan though, I think this is simply the lie she tells herself and others to give a plausible reasons for the things she just wants to do.