I can't understand this. I do not view my coworkers as part of my personal life, so while I enjoy working with some, I wouldn't say I'm sad if they leave. This sounds unhealthy
When you spend 8 hours a day around folks and become friends with them, it's natural to miss them when they leave. It's OK if you don't have any meaningful relationships with your co-workers, but, to me, that sounds unhealthy.
While you aren’t seeing people every day (the company is distributed), the relatively frequent meetups in cool places are a massive highlight, and just make your relationships that much stronger.
There are a lot of folks who have been around for ages — even if you aren’t working with someone directly anymore, you’ll frequently see a familiar face (and helping hand!) on the other side of the company.
So the grief of leaving these relationships is acute, especially if you’ve been around for a while. Processing that grief is healthy — and I might suggest that not having any kind of relationship with your coworkers is unhealthy. Or at least speaks to a cold culture somewhere.
This might not be a "them" problem.
I'm not advocating that your coworkers have to be at the same rung as your family or [in-group X] but it's weird/sad to many reading this that you're okay not caring about the people you spend your days working towards a common goal with.