Not sure what this post is about, OP… What are you actually asking?
Paternity leave is obviously vital if you’re a decent parent and partner. If you have it available you take it and you focus on your family. Your mentioned group of coworkers sound like fucking degenerate scumbags stuck on a pointless treadmill. I feel sorry for their partners and their children.
You should take some time to consider why you didn’t have a visceral reaction of outright disgust and had to come here and ask for others to chime in. Tune in, bud. It’s all about your kids now. Don’t look for worthless approval from worthless people.
Not assuming. I just didn’t see you express that disgust, so even the omission says something.
IMO you need a lot more passion in your response, here and IRL to colleagues. These are obviously broken people around you. You smiling and nodding and coming here to quietly discuss away from them helps perpetuate their nonsense. Alternatively, if you had a gut reaction of “Dude, what the fuck are you talking about? How are you supporting your partner if you aren’t taking that full leave? A newborn is 24/7 physical/emotional/mental gauntlet. Are you just leaving them to deal with all that, that’s horrible, man… Do better.” might have knocked some sense into them.
We break these toxic cycles by speaking to our peers with confidence and putting idiots on the spot by holding a mirror up to their childish bullshit. Sounds like you have the right position generally, I’m encouraging you to express it openly and forcefully to be a part of the change you seem to be in support of.