I think the parent you replied to was mocking his parent comment with that statement, because that was the gist of the grandparent comment.

I read the comment as being a satirical way of voicing critique.

They are quite obviously suggesting that they think your comment was saying that, they're not expressing it as their own opinion.

They were clearly paraphrasing your statement.

They don't, you do, as you wrote in your previous comment.

He's saying the exact opposite