It's great making assumptions when you know nothing about the dynamics between two people, their social interactions, their history and basically anything else isn't it?
I mean, you could have just asked. But insulting random people you know nothing about is much less of a douchebag way to deal with it I guess.
I read it much the same way, as a rather insulting thing to say, especially since you didn't go into what was said afterwards and you didn't preface the kind of relationship you had. It's not on the reader to understand what you meant, it's on the writer to write what they mean in a way that the reader understands the intent.
I know you specified this was 10 years ago, but I can't think of a single situation where this would not be a douchebag move.