I think you’re missing the point. It’s not that men need to treat women “equally”, it’s that the reason mansplaining happens is different to the reason that generic pedantry happens. They can happen at the same time, but the general idea is that mansplaining is pedantry with a boost of sexism, intentional or otherwise, not simply being pedantic to a woman. The difference is subtle, and luckily the solution of just not not being an ass to people solves both issues quite well but it’s still good to try identify how much of one or the other is present when you slip up so you can address the correct problem.

Put it another way, you also shouldn’t be treating an old person like a baby when helping them with their phone, or a child like they’re stupid and couldn’t possibly know things a grown-up doesn’t. All of these are genderless examples of how disrespect can come from several angles at once and there is also the gendered scenario we call “mansplaining”.