Yes but the point of my suggestion was as a way for you to get over your exposition issues. The point wasn't, "Write it this way, make her angry about rape" it was for you to use the opportunity to use the explanation to further character development. If you saw it as that as opposed to trying to simply define something, I thought it may help make your writing sound less forced.
So she isn't angry about rape. Maybe she is motherly (and again this is NOT to say she is, this is an EXAMPLE): "Oh my goodness dear, you really are clueless aren't you? Okay, now have a seat. Rape is a very difficult thing to explain really, but I shall do my best. . . " Again here we now see the character as a motherly figure taking pity on a poor ignorant boy. We learn about her character at the same time as learning about the meaning of rape.
Maybe she is a valley girl: "Like oh my god you don't know what rape is? Like okay there is something so totally wrong with you!"
The point is use this opportunity to further something about the character, NOT exposition.
ETA: you say her goal is to educate fine, but coming from a long line of teachers I can tell you there are many different teaching styles and they all come down to personality. So you need to ask yourself, how does she view this boy? Is his ignorance frustrating, understandable, sweet, annoying, absurd . . . how does she view it? In her view of it then she will decide how to offer her explanation, she could be annoyed, motherly, condescending, amused, horrified and yes, even angry. Just because she wishes to educate doesn't mean she is suddenly a robot with no feelings.
This is the problem with a lot of SF/fantasy I find where one character is familiar with a world when another is not. This one character will explain all the facts very matter of factly about this world as if the stranger has happened upon the only tourist guide around. People have feelings. They've had rough days, or good days. Someone asks you what the local currency is they aren't just going to necessarily answer, "Why it is the Bleepnet. Of course in the provinces they use the Gurmblat." They'd be more likely to say, "What? Oh, the Bleepnet. Seriously? You don't know that?" or something else. They are people, not just exposition machines.
Lastly I would suggest you reread my original post and see how what you gleaned from it and what I actually expressed were two separate things. I reread it myself to make sure I hadn't been unclear, and I truly don't think I was (this time, that's not to say I haven't been in the past

). Part of writing is understanding criticism. That seems straightforward, but we as authors have to train ourselves to truly glean the advice being given. For example I had a very difficult scene in my first book that my editor wanted me to cut down. She gave many examples how to do so, but I didn't like any of them. However I understood why she had made those suggestions, and the goal behind them. I was therefore able to make my own cuts the way I wanted to, and still do what she requested. I used the spirit of the suggestion, not the suggestion itself. We have to deal with people critiquing us all the time, some people we agree with and others we don't. But it helps to make any final decisions on that front to understand what the person is trying to tell you in a more general sense, instead of focusing on the minutia. You may think it absurd for example to cut a certain character per someone's suggestion, but still you could understand why the person didn't like the character to begin with. This can then lead you to either make changes in the character himself, or realise that the reason the person didn't like the character was because you know she's the kind of person who doesn't like people named Bob, and therefore you'll leave things as is.
Anyway, just a last thought.