now, am I correct in assuming that what he actually suggested (rather than what was reported) is that they should man up and stop purchasing their electricity from AZ as well?
This is far different from threatening to cut power...
Yes. His actual suggestion was for LA to “man up and stop buying power from Arizona, since they were supposedly “boycotting” the state. Since he is only one member of a board and the Los Angeles DWP actually owns the power generating capacity. A percentage of a nuclear power plant, a part of a dam, and a part of gas generator totaling 25% of the power used by LA, he can't do anything else but make the suggestion.
This what he said on KFI some days ago.