Funny Ha Ha

This is supposed to be a joke.

In school, we had an assembly on bullying. The teacher spoke to a young gay boy, being bullied because of his sexuality.
She spoke at length about his life, and the verbal abuse he suffers. She then asked a question, "How do you think he takes it?"
Apparently, "Up the arse!" wasn't a suitable answer.

Now, I'm not averse to jokes in the slightest but this is not funny; hence not a joke. What I don't find funny is that at the start the child has being bullied because he is gay, which for a start is unacceptable as homophobia is wrong as it shows a lack of understanding and is a blatent display of ignorance.
The teacher then discusses the issue with the class, but the 'punchline' - "Apparently, "Up the arse!" wasn't a suitable answer."" - implies that the bullying is fine, because it is 'funny' and a 'joke'.
I'm no prude and I love comedy, especially if it is smart and witty; I take issue with the fact that this is viewed as humorous. Homophobia and bullying are anything but funny, they are major problems and lead people to take their own lives. I would love to know how that is funny.
The way that people can see the quoted 'joke' as a bit of fun does worry me, words and how they are read and understood are crutial and paramount to how we communicate and engage with the world.
People should really look at what they read more carefully, just because somebody says something is a joke does not mean that it is.