> My gripe with the antagonistic "work is not your family" approach is it sends the signal that the people I meet at work will never be my family.

This seems like a safe assumption? I guess you can marry a couple coworkers in the course of a career but how else are they going to become family?

I don't see that as antagonistic. Work isn't your family. The purpose and circumstances are entirely different. It doesn't mean throw all your coworkers under a bus but the relationship is fundamentally different.