Responses

It just makes your comment seem like you are not okay with it and you want people to notice that and be aware. To be fair, I wouldn't condone such a relationship in rl because it doesn't seem right to me, but I am able to separate fiction from rl and a lot of people are as well.
For future approaches with similar comments of yours, say that you are actually not bothered by it and to add details stating your own opinion with it, so people do not misunderstand your actually intentions and meaning with your comment.
You know Kousuke is actually in a relationship with a minor...