Man, y'all are taking this wrong.
The mecha is powered by magic.
His magic gets stronger the more he makes drugs and fun at the brothels.
Or simply his mecha is powered by drugs & sex.
And this chapter is just to showoff that the elves were the ones that were behind the drugs and sickness that all the non elves whores were getting. And if that wasn't enough, to show how they even tried to screw up the MC when he got an elf lady to cum.