Maybe to you, but not to Luke and not to Lorelai. The point of this is to show that those two are still connected heart and soul, and would drop anything to help each other, regardless of how uncomfortable they feel or how bizarre it would seem. And I doubt any of them (Rory included) are thinking about how inappropriate it is for him to be there.

Especially Emily, who accepts his offer of help. I guess someone forgot to tell her that Luke doesn't belong there. Or that she doesn't like him.