the controller,
Do not think of pitch angles, they are the result, not the cause, and they are quite confusing, and actually, I would bet not one ppruner in 100 can tell me the real angle of attack (pitch) angle the blade assumes in ANY flight condition.
It is more intuitive, and more accurate, to think of the rotor making a stream of air run downward from it. Think of that stream as what supports the helo, as if it were swimming upward in a sea of air, and by pushing air downward, the helo raises itself. If the helo is heavier (for a given size rotor) it must toss more air downward, so the stream is pushed faster.
When VRS is encountered, it is because the rotor is lowering itself downward faster and faster until it catches up with some of its downwash. When the rotor is shooting downward at more than half its downwash velocity, it begind to catch up and the ring starts to form. By 75% of the downwash speed (maybe 800 fpm in a light helo) the VRS is truly encountered.
If the helo is heavier, it takes more descent speed to catch up with the faster downwash, so VRS is HARDER to find in a heavier helo.
If you are at a higher altitude, the air is thinner, and lighter, and so it must be pushed faster by the rotor, so VRS is HARDER to find at higher altitude.
Why do instructors teach otherwise? because they mix up VRS with running out of power to hover, where the aircraft falls through as it tries to hover. Falling through is EASIER at high weight, because it takes more power than normal. Falling through is EASIER at high altitude, because the engine makes less power, and the rotor needs more.
Don't mix up VRS with "Falling Through" or "Over Pitching". They look similar enough, but they are caused by two different things.