Hi OP
I too think you are massively over-reacting sorry.
My 4 yo is probably a lot like your DD in that she's astonishingly verbal and can formulate the most incredible ideas and then express them with amazing clarity. Most adults say she chats like a grown-up.
Which makes it very easy to forget that she's only 4 and that emotionally, she's a long long long way away from how mature she sounds.
I have to remind myself of this when she's being a very very typical 4 year old and suddenly starting to get annoyinglly silly at bedtime, or when she suddenly says something startlingly rude/cheeky. It's so normal for her to sound more like a 6 or 7 year old (who I would pull up if they were that rude or blunt) that when she actually talks like her age, it's a shock.
4 year olds and 5 year olds (hell, 6 and 7 and 8 and 9 year olds) say silly things, things they don't mean, they honestly don't think before they speak a lot of the time no matter how gifted or verbal they are.
I myself remember being about 6 (and I was another highly verbal and bright child) and my mum came out of the bathroom from doing a poo one day and I said, before I could stop myself (I remember the sensation) 'You smell!' She hit me on the face (which is a whole over thread) and I could see the shock in her eyes that a little 'grown up' child like I was had said something so crass. I was shocked too, more by the sudden blurting out that I hadn't meant to do, even, than her hitting me.
Please don't go overboard on this. Your DD clearly feels bad (which I'd argue she shouldn't anyway) and has apologised (which I'd argue she didn't really need to do in the first place).
My DD is fond, at the moment, of telling me she 'feels dead'. She may chat like a child twice her age most of the time but when she's tired she just says any old crap and often she likes to shock me too.
So yes, in a nutshell, YABU but I think you know that? Sleep deprivation is a bugger, good luck.