I agree with PPs that an apology, just in words is nothing. But often even if it's not heartfelt, it's an admission of respect, or of needing to be at peace, or something... for your DSD to apologise would be an acknowledgement that she needs to do it, to be able to communicate with you. It's making her take just a teensy bit of responsibility, instead of expecting you to just forget about it, in which case she doesn't have to do anything.
So, for that reason apologies can be important... other times not so much. I agree very much with Sloane, that it's what's behind it that matters.

I've read some of your posts over the years too, and I'm not surprised you feel like this... I don't think you're being silly, I think you've just reached *that* point, you've drawn the line & it's up to them to give a bit now.
If your DH wants to accept it, forget it & move on, then he can choose that for his relationship with her - he can't choose that for you though. That's your choice to make.