They typically don’t teach people the difference between turning while braking and a braking line until later on in a racing license course. They just blanket tell everyone “no movement under braking” until you learn enough to understand expected track trajectories, and then they teach you what movement under braking is legal.

This isn’t turning while braking, this is expected braking line. The unexpected braking line is someone braking in a straight line, perpendicular to the corner for this sequence. I think for this it’s a bit of both faults, but both people have a case here. In the end it would be down to the stewards if they cared at all.