There's really nothing wrong with make minor edits for typos like that provided you explain it in the edit field as you did AND make a new post to the thread telling about the edit. Without the new message, those who have already read the original post will never even know the edit has been made.
The only time where making any changes at all (even this correct way) would get you in trouble is in a debate thread where you change the meaning of the original post in any way that could affect the discussion after someone has already replied (as you could change your post to make it look like they misread you original statement).
So it was because I did not post a new message to tell that I edited. Missing this step caused the problem. I understand and I get why this is an important rule for many reasons, including during a heated discussion, or like you said... a debate thread.
My apoligies for interupting the thread you started nemesisfirestorm.