Back to you SSG Version 1.0-1.9. Inside joke
The reason is that those two speeds, Vmcg and Vmca, are determined by thrust. Increasing the thrust on the live engine would increase those numbers and, hence, affect adversely directional control. Further V1, Vr, and V2 are related (Old Smoke, help me here) to Vmcg and Vmca. V1 must be greater than Vmcg for you directional on the runway using aerodynamic controls only; Vr and V2 must also exceed Vmca by certain margins to ensure control airborne. If you increase thrust on that live engine, you can see that the numbers the take-off was predicated on have all increased and IF you followed the planned speeds at increased thrust, it could be bad.
GF