Today I was a bit surprised while searching a term within the utterances of God in Genesis, that Gen 22:17 did not appear in the results. Upon closer examination, I found out that the text is labelled as having the Angel of the Lord as speaker. Now, it is true that the speaker is referred to as the Angel of the Lord in the text, but it is equally true that it is understood that the utterance in question is God's.
When I look up who is the speaker in Isaiah 1, the text is labelled with God as speaker, not the messenger, Isaiah. So, it is a bit inconsistent.
Now, of course, it may be desirable in the context of some studies to distinguish between the messengers and the person they represent. I am wondering if in the case of the Angel of the Lord and passages in which it is clear that it is an utterance of God, it might be best to label the text with both as speakers?
I know that this could open also a can of worms: should Jesus' words also be labelled as God's? Should prophecies be labelled as both the prophet's and God's words? But it seems to me that at least in the case of the Angel of the Lord for which it has long be recognised that it is often difficult to determine whether it is not an actual theophany, it seems legitimate to proceed as proposed.