Therein lies the danger. An outsider with little knowledge cannot make a good judgement. Their judgement will be based on intangibles, such as "something similar happened to somebody I know, so I tend to believe X's account over Y's account".
But that's not proof, or evidence, or anything really. It's just naked bias from a different situation applied to an unrelated one. Saying "history is replete with examples" is exactly that. If that is going to be used as a metric, then it is well worth it for men to consider that mentoring women carries with it a high degree of risk. No matter how you behave, a single accusation from somebody willing to lie or exaggerate--for whatever reason--will be supported and amplified using this same historical rationale.