I agree that to call bunch it all under PND is not right.
It should be handled distinctly, because the challenges a man experiences pre, during and post birth are different.
Responsibility for bills, becoming a father and what that means, examining their own relationships, which change dramatically with a child, societal expectations of being a provider when your in a precarious financial situation, loss of freedom,
Women, for all the shit of actually going through it, do actually get a modicum of understanding - men are left to get on with it to a large extent or are blamed/shamed when they find it difficult.
I don't think poor mental health should be a competition, but I reckon it will help more people to have a dialogue of " yes, life has changed dramatically - get help here"