"Mansplaining' does not mean 'a man explaining'. It is not frustration that the voice belongs to a man. It means a man explaining to women something that those women are experts in, and doing it in a way where he believes he is educating them as if he knows more than they do.
I have seen men explain PND, periods, pregnancy and menopause on here lately. Most of the time they've got it wrong.
If you, as a man, try to 'educate' women about women's issues you throughly deserve to be called a mansplainer."
That's still quite bollocks though. People less educated or informed about a subject lecturing others who are more educated or informed is a fact of life hardly exclusive to women.
My brother who had an accident with a saw while working as an engineering apprentice was told by a new non-engineerig teaching assistent at college that he should of been wearing gloves. Clearly she neglected to think a saw capable of cutting through metal would be capable of cutting through a glove, he was wearing gloves.
In my experience more confident people deal with this better as they tend to aggresively assert their value and capabilities for example by cutting people short and reeducating them when they try talking out their arses. People see that and don't bother talking cr@p in future.
Again in my experience I don't think women on average are as good at asserting themselves as men. Leadership in any sense and that includes 'knowledge leadership' (been a leader or expert in a certain subject for example) is inherently competitive. Men who lack confidence struggle in that regard aswell from what I have seen.