It's not more complicated than that. There is a confusion between incremental torque, which does get reduced (as correctly noted in the above) but only because the increments get reduced, and stall torque or holding torque, which in almost all cases do not. The latter are the ones that people generally care about, but because they read about a reduced incremental torque, they get the misconception microstepping creates some torque compromise.
But a full-stepping motor also has bad incremental torque for small displacements; by disabling microstepping you're just forfeiting the option to command them.
If anything, microstepping lets you run even closer to the motor's torque envelope, because you're less likely to induce a dynamic stall by either exciting a resonance or letting the stator's magnetic field get too far away from the rotor angle.
As long as you are below the maximum pulse frequency that your controller can process, there's no penalty at all to microstepping.