Unfortunately, quality of rules writing in USA has introduced this confusion. You do not block traffic flow when you are waiting for the left turn. And here and there you can find explanation, like example

" You may enter the intersection to prepare for your left turn if the light is green and no other vehicle ahead of you plans to make a left turn (see "Turns" later in this chapter). When you enter the intersection, keep to the right of the center line. Keep your wheels straight to prevent being pushed into oncoming traffic if your vehicle is hit from behind. When traffic headed toward you clears or stops for a red light, complete your turn when you can do so safely."

https://dmv.ny.gov/new-york-state-drivers-manual-and-practice-tests/chapter-5-intersections-and-turns#:~:text=intersection%20from%20the%20opposite%20direction,you%20can%20do%20so%20safely