I found motherhood hell - so, in a way, I do agree with that article but, as trefusis says, in the context of having had PND. I think it's hard for everyone but, without PND, I think it's easier to adjust and there is joy to be found in your situation.
With ds1 I think it was a combination of a hormonal/chemical inbalance and the psychological impact of being utterly unprepared for the reality of having a baby; I was knocked sideways by the sleep deprivation, was frightened of my baby, had no idea how to do anything, was pertified to be alone with him, hated it when he cried etc. So it was hell and it remained hell for a long time - didn't really start to feel human again 'til he had turned two.
I don't think there is a conspiracy of silence these days. I think it's more a case of pre-baby mass denial! People told me how hard it would be, how tired I would be, how I would wonder what I had done with my time before. I was totally dismissive. Not because I didn't believe them but because I couldn't believe them. You can't grasp it 'til you've done it.
And I don't believe, as the article seems to imply, that it's only career high-fliers that find it hard. I worked but I wouldn't describe myself as a successful career woman. I don't believe that lessened the impact of the shock I went into upon having my first baby. Implication seems to be if you had a crap, boring, mundane job before you'll take to motherhood like a duck to water
Interesting article though - and I particularly liked the celeb mums bit. When I was in the depths of PND I read a Radio Times article with Imelda Staunton who had suffered terrible PND after the birth of her daughter - she said there had been times when she wished her dd would die so they could be sad for a bit then get back to normal. Her bravery in admitting those feelings helped me so much.