Why only do this "as long as they have a turn signal on and [you] have room to move over"?

Why would you not have room to move over? Because a car is to your left? If so, that indicates you stopped in the wrong position in the first place. If you got there first, and a car came next and stopped to your left, you stopped too far to the right. You should stop far enough left to force the next car that shows up (that's not turning right) to stop behind you, not next to you.

If the car was already stopped and you stopped to its right, then you should have stopped behind it. In either case, you should never be in a situation where you have no room to move over far enough to let right turners pass you on the right, unless the lane is too narrow to be safely shared by a car and bike side-by-side, which is very rare for a right lane at an intersection that allows thru traffic as well as right turns (which is the situation we're talking about).

Serge