Work can be a bit isolating when you have a very different background from a lot of your coworkers. Having a group that shares some aspect of your background that you can talk to about that shared perspective with can help a lot.
Companies should go a bit farther than making groups that are built race/religion/gender lines to bridge that gap. I've been at a lot of companies where there was some shared activity that "everybody does" after work - something that not literally everybody actually does. There should be other ways of including those people.
Often something like that can reflect a cultural background or gender (be it "everyone" is in a fantasy football league or "everyone" is competitive about a certain video game or "everyone" goes out drinking on Thursday).
If you're a member of a small group, be it because you're black, female, LGBT, have children (or don't), whatever it might be - it's easy to feel lonely and marginalized and like you don't have a community at the workplace; it helps if the organization promotes a way to feel like you do.
So that it's not just "oh everyone is talking about that thing I don't do again".
As investment into the company increased, more juniors were hired that had the similar life situations, liked to do similar activities, etc. My attachment to the company became much stronger after that.
> the fact you work for the same company can become just a footnote if you want it to
... until you have an HR complaint, or need to manage a layoff, etc.
Too small right now to have ERGs that don't apply to large groups but the soccer team, the basketball team, our running group, and those who cycle tend to form friendships that Grease the wheels of interaction at work, apart from it just being nice to have friends.