I respectfully disagree. This is only true if the flight is eventually completed, as in your examples. If it returns to the gate and cancels, it doesn't count as flight time.
The answer on the top of the page you quoted, A50 is NO. The question was "A flight pushes back and taxies to the runway under its own power with the intention of flight. Before taking off, the flight crew is notified that the flight is canceled and the aircraft returns to the gate. Is the taxi time counted as flight time?" The answer was No because the plane did not takeoff or land.
My airline also DOES (thankfully) include this as flight time, because our contract defines a rtg as "block" and uses block instead of flight time, which includes "attempts". However, they are not required to do so.
The FAA interpretation you cited did not consider the case where the flight returns and cancels. In all three examples the airplane eventually took off.
This seems unfair. Why should the time be counted differently if the flight cancels? However, ALPA says it doesn't count, and I assume the FAA vetted their answer.