But I think it's really absurd to suggest it is something only men do-- to the point of referring to it as "mansplaining".

Sure. Similarly, I think it's absurd to suggest that complaining loudly and aggressively is something only women do, to the point of referring to it as "bitching."

And yet, terms like this are common in our linguistic environment.

Of course, that's not in and of itself a good reason to accept them. My culture no longer uses "Jew someone down" as a way of describing sharp negotiation practices, for example, because it's seen as expressing and encouraging a view of Jews that we collectively no longer endorse. (Though we still use "gyp"in similar ways.) Many communities reject "bitching" for similar reasons as applied to women. And we could certainly reject "mansplaining" as harmful to men.

But it's also worth asking where our energies are most usefully spent.