You talk about being fouled in the act of dunking, and that certainly happens.
But you then apply a very narrow definition, referring only to the final movement.
Fouling ONLY during the final movement of the ball down into the ring, AND doing so in a way that stops the ball entering the ring, would be difficult.
Unless you're talking about a much more extended form of dunk, such as a "tomahawk" type action? I can understand there that the offensive player has the ball above the level of the ring for an extended time and distance, and could easily be fouled in that phase. But such shots are not inherently more accurate than say a lay-up, so I can't see the argument for special consideration.
If your argument, more broadly, is that deliberately fouling a high-percentage shot, such as a dunk, should be more fairly penalised,
then I agree.
But its difficult to adjudicate, particularly with the broad definition given to the act of shooting.
NB: That is not, and never was the definition of "Hack-a-Shaq".
It may have taken its ultimate name from Shaq, but started long before, and generally refers to any strategy to intentionally foul a poor freethrow shooter. Moreover, the fouls were generally off the ball, to avoid the risk of a made shot or a flagrant call.
You may be thinking of the more general tactic of fouling a shooter to prevent an easy dunk or layup? I don't know if that has a pithy name.