You know, the more I think about it the more I think it was very spot on for Emily to be so disdainful of Luke. Maybe she could have been kinder, but from her POV I'm not sure there was a reason.

He was (a) as I've said previously, weirdly inserting himself in a family situation where he didn't belong. Yes, Chris should have been there, but that doesn't make it Luke's place to be there. But (b) the last contact Emily had with him was as the man that broke her daughter's heart because he pushed her out of his life.

I actually think it will be all that much harder for Luke to gain Emily's acceptance the second time. She, and Richard, had already gone through the process of accepting that he was Lorelai's choice, not theirs, and they would deal with it because he made Lorelai happy. But instead from her POV he betrayed that acceptance by his actions with April and toward Lorelai and by breaking Lorelai's heart. She doesn't know all the messy details. She just knows that. Which makes me really realize why she reacted the way she did.