> This includes holding future promotions and days off against them for doing the very things society thinks they should be doing - namely, parenting.
You ignore the parent poster. His point seems to be the idea that a person can take upto 3 months off of work shouldn't be equivalent to someone who didn't take that 3 month block off regardless of the reason, child rearing or hiking the Appalachian Trail.
If I took that much time off and a coworker didn't, especially year after year, I wouldn't expect them to get more raises, more seniority.
This idea me at home taking care of my kid is the same as people at work is silly. Promotions shouldn't be given just because someone has worked at a place for an amount of time. The exception being cost of living increases. Seniority on the team, responsibility and the increases in compensation that come with that should be according to ability, time dedicated and skills, etc.
On the flip side, if my time is spent engaged with my child then it can't be on increasing my career if I'm at home full-time parenting. This isn't about working parents but, during maternity/bonding leave. It's either one or the other.