Not mocking anyone. I am actually a fan of DMs filling-in stuff. Maybe I did misunderstand you, though, because I don't remember now exactly what your point was or why I thought it was ok to respond as I did. Certainly, no offense was intended and I was absolutely not mocking you. The psychotic demons that were tormenting me last night have moved on to greener pastures today.
No "dismissive sarcasm" or sarcasm of any kind for that matter, was intended. For some reason, I just found it amusing the way the 1Ed. DM Guide falls back on DM Discretion as a last line of defense, with which, incidentally, I happen to be in full agreement, even if I sometimes chuckle at it.