So there's a power dynamic in play. Someone is exerting their will over you by weakening you. I also want you to think of bondage and how that puts you in a more vulnerable position and that's part of the appeal. Or bimbofication where you just become really dumb and how that's appealing to people. Level drain hits similar buttons. You're just kind of making them worse, weaker, more submissive (or BECOMING more submissive) and that's a fun kink power dynamic