It depends on the site but when I was a SAHD, I found many of those parenting sites were not welcoming to dads, even dads doing the exact same work as the moms. Moms there wanted a place to vent about their husbands and men who were pulling their fair share or were handling most of the parent duties simply weren't allowed.
one of the better places I found found was Daddit on reddit, though I haven't been in a while.
This, it's well known that women want to vent and men want to fix the issue. This difference in communication and perspective has been supported in various research.