That is not correct. If an overreaction happens the blame would be on the person who overreacts. I do not think that even if we had evidence that disproportionately harsh consequences would prevent sexual misconduct, that the ends would justify the mean if we ruin someone's life by applying an unfair punishment for their wrongdoing outside the legal boundaries.
I would disagree that an isolate incident of inappropriate touch or a suggestive comment or attempt to initiate a sexual relationship with an underling would ruin the victim's life or career. It is a different story if it is proven that the harraser also ignored the rejection or if they used their position of power to pressure the victim for example by threatening to ruin their career. Not differentiating between these two scenarios would not be fair to the harraser in the first scenario and it wouldn't be fair to the victim in the second scenario.
If lives are ruined, it is the harrasser's own doing. It is precisely the fact that such incidents are routinely shrugged off that harrassers feel emboldened to continue. Perhaps if they realized their careers were on the line, they would check their hormones and act more appropriately.
Furthermore, this line of thought completely ignores the lives and careers that the harassers have already ruined. By treating junior colleagues as sexual opportunities, this robs the field of future talent by pushing them out.