If that text is ever not sarcastic, how would I ever know, if it existing makes it sarcastic?
guess you hvent been aorund gamign for too long, cause if a developer in a game tells you "this is what you should do next" or "this is the main point" or "dont do this and this", pretty much everyone will do and try first anything that they arent supposed to do and will do all the sidequests, eplore places or anythunng that is not the intended way.
you arent wrong, you jsut trusted the signs a bit too seriously there.
baisclaly people in game susually jsut try anyhting, if it's forbidden or not. "yo aint my real dad you cant do me what to do" kind of reaction very often. :-)