Nicky - i agree with your last point about times changing. It will be very interesting to see the take up of transferable parental leave which is available shortly. It would be great to see a really huge proportion of couples take up their entitlement to share parental leave.
I know there's a backdrop of a patriarchal society, BUT I don't think we can underestimate the power of the decisions which couples make, the way they choose to shape their lives. At the end of the day, couples of childbearing age now, in 2015, have got a better than ever before chance of shaping their lives regarding children, work and domestic tasks. Life isn't perfect, but in this regard things are better than they've been at Any point in history.
A woman of childbearing age now will have had equal entitlement to education as her partner (in fact females currently outstrip males in educational attainment at virtually every level.) They have access to the same professions. A woman who is pregnant now can share parental leave and between them, the couple can take a year out of the workplace with their salary and status guaranteed on return. All of those things are massive strides forward, and so very different to how things were when those of us with grown up children had our babies and returned to work.
To return to the OP- I wouldn't get upset by such comments; maybe these people are just filling space in the conversation and not meaning anything remotely negative.
And remember: other people's perceptions are exactly that: perceptions. No one is living your life but you. I've no doubt some of my friends felt sorry for me when I returned to work after the standard 12 week maternity leave in the early 1990s. And no doubt some of them felt sorry for me a few years later getting 3 little children out of the door and off to nursery before doing a days work. But of course what they didnt experience was the satisfaction i got from continuing in my career. And they didn't see first hand the great experience my children had at their nursery.
Why would they? We're all busy leading our own lives, and tbh we can't actually know what it feels like to be anyone else.