Some workplaces are really good at getting employees emotionally close to one another. Sometimes that's caused by hiring super-friendly people who will make friends everywhere they go. Other times, it's boosted by a bunch of employees who don't have any other friends outside of work, so they rely heavily on going to the office to have a social life. Most of the time, it's not that nefarious. A lot of workplaces just have a very social culture, and there's nothing inherently wrong with that.
Things start to go downhill when employers insist on calling their staff "a family." I know they are not literally calling them their family, but it can be a slippery slope to manipulate workers into doing things because they feel like they have familial obligations to do so. One teacher called out the precarious nature of the "family" label, and her coworkers were not pleased to hear her pushback.