Can anybody explain the structure that takes place here. Is it correct and why is "would" there? What kind of rule could be there?
The full phrase was:
I guess I am a little bit disappointed he would say that.
It was used as an opinion on someone's comment in a video (doubt that I can reference it due to having lost the link). The meaning is perfectly clear, though the grammar rule which allows to use "would" in this case is still a mystery to me.