No, that had nothing to do with emotional attachment. It’s a short phrase to remind people that they can’t make each device special with one-off because it needs to be repeated/destroyed all of the time.
Separately, cattle vs pets is much older than containers. It got popular with ephemeral EC2 instances when people were first forced to grapple with lifetimes of VMs measured in hours and the ability to scale massively as needed.
A little of both, I think. I remember having decommissioning ceremonies for long-lived, specifically-named servers, and I remember the era when people were proud of astoundingly long uptimes. Both of those things are aspects of pet-hood that treating servers like cattle changed.
I never took that as dealing with emotional attachment, it was just a shorthand to express that at any moment you would kill cattle so don't do things you can't easily replicate.
