Love these arguments where everyone looks to find who's right when, depending on your point of view, the truth is either everybody's right or nobody's right.
Demanding a degree in physics prior to learning how to fly a helicopter is impractical, yet understanding why things happen the way the do with helicopters is necessary. To make the concepts understandable, answers are diluted quite a bit in most cases, and in some cases are complete lies. But they still get the point across.
This idea of looking at the difference in height between the tail rotor thrust and the horizontal component of main rotor thrust has huge merit. If they act at the same height, then when there is no net lateral force, there is also no net rolling moment. Thus you hover with skids level. (At least within the many approximations that have to be made.)
Is that accurate with physics? Yes, but it is far from the whole story. Just knowing the difference in height doesn't help much in designing helicopters, but it does help in understanding a small part of helicopter flight.
So is the right answer that those two forces create a moment about the center of gravity and the vector sum of those moments is the net? Well, that is a right answer, but there are others. Because of all the approximations still being made, it would be valid to call this a wrong answer as well.
What's right really depends on why you need the information. If you're designing helicopters you need way fewer lies and much more accuracy. If you're trying to learn to fly helicopters, a general understanding is sufficient.