I think you are mixing issues to be honest.
Its factual that most people at home with new babies are women. It's just a fact.
SPL, hasn't taken off as wished. For many reasons, including that women are choosing not to give up one of the only perks they get as women.
Yes, we need to address men mot parenting equally
That doesn't mean that parenting groups have to be mixed and everyone r has to share experiences even though they are different.
Women who have given birth should be able to meet with other women to discuss these experiences. And most don't want to do it round men and most men wouldn't feel comfortable
Its good that women who have just given birth can find and yalk to women in similar positions. There can also be mixed gender groups
But quite frankly, children will learn more about equal parenting within their home. Not from dad feeling like an equal at aren't toddler groups when they were tiny. We change things by teaching the next generation of kids.
If a mixed sex couple show good healthy shared parenting in the house, that's is teaching the child. The mother could even be a sahp and the couple could still model this
These groups are a choice. Not compulsory. Do you think kids who don't go really suffer?
Parent toddler groups are not the be all and end all and teaching about parenting equality doesn't start and end with these groups.