Sorry - posted too soon (bloody phone).
What I was trying to say - I do kind of understand the OP's original point, though agree she phrased subsequent posts badly and in an inflammatory fashion (we are all 'raising' our children whether we work full time, part time or stay home full time!).
When I was a WOHM, when DS1 was a baby, I'd taken a year's maternity leave. During that maternity leave I knew exactly what the SAHM role involved in terms of day to day logistics - but I still had a career to return to. I'm now a SAHM, and have effectively shot that career in the foot (I was in HR) - when I do go back to work, I will have to do several years at a much lower level to work my way back up to where I was at, simply because of the choice I took to step away for a number of year (my choice though, of course, and I acknowledge that I am extremely lucky to have had the choice). That's if I manage to get back into the industry at all.
As a mum on maternity leave, therefore, I wouldn't have had the understanding of what it would feel like to have no potential career return on the horizon.
As others have said, everyone's situation is so different that you really can't compare them. Of course the WOHM who fits work around preschool and/or school aged children and has no other help (ie cleaner) could argue, accurately, that she does precisely the same things for her family as a SAHM with preschool and/or school aged children. And of course the WOHM with younger babies/toddlers who works and uses childcare for their DC is not doing precisely the same things for her family as a SAHM who is home full time doing the childcare.
For what it's worth, I don't think I'm doing a better job as a SAHM than, say, a loving nanny or fabulous childminder or brilliant nursery would do for my children. When I worked, DS went to a (fantastic) childminder 3 days a week and I actually felt that he had a better, more balanced time during that period than he did home with me full time...