That's exactly why one has to do everything slowly.Absolutely.
In theory, the moto should be behind you. They cannot see my turn signal on the side of my car.
A moto crashed into me passing me on the LEFT as I was turning on a four lane-two way street.
You can't make a a quick left turn, even if oncoming traffic signals you to go ahead. You must still be aware of your situation by looking at all three mirrors, and proceed slowly.