my 2 cents :

it may simply be a missundertanding about the FEELING you get of torque : with a 15/44 ratio, there is no doubt that you get more pure torque Newton/meter on the wheel, but less total end speed. with the 15/44 ratio, you may have the feeling that the motor quickly reaches his highest RPM. some may think too quickly. this can lead to the feeling of no torque and not enough speed...

on the other hand, with a 25/44 ratio, you will get a bit less torque and much more endspeed ( and a burning hot motor... ). But the feeling you get is more satisfying : you can feel the motor battling to reach its highest rpm and you see the vehicule driving fast before reaching the motor's highest RPM. You have the feeling to drive on torque, not on RPM. just like a diesel motor.

I proceed this way to gear : I put the highest pinion I can without overheating the motor !!