Note how Person B makes a point to mention there are many good-hearted teachers who would not attempt to abuse their power in such relationships, so they shouldn't feel this absolutist law is aimed at them. How nice to make that clear. Yet because the law is so non-negotiable and absolute, without even bothering to ask for an investigation, or even if there is any plausible reason to suspect foul play, before dragging someone "downtown" these good-hearted teachers are going to be punished along with any bad teachers. And all on that infamously draconian "erring on the side of caution" schtick. So they are effectively delivered a slap on the face after that disclaimer of consideration.

This is self-contradictory. This law and laws of its kind very much are targeted at the good-hearted teachers who would not abuse their power. Teachers taking advantage and abusing their power already are punished by laws against harassment and sexual coercion. It is only the good-hearted teachers who are caught in the net of these laws.

The usual excuse is that since these kind of laws reduce the burden of proof they make a conviction for actual abuse easier. I don't think this is proven by any means, but even supposing it is, it remains a very strange proposition anyway. It would be like convicting for murder not on the presence of a corpse but on the presence of victim's blood.