That's a fair point, but there are also many of us who want to be friends with our co-workers, and not just see them as little automatons that we interact with for 8 hours a day, 5 days a week, and never again.
Personally the kind of companies I prefer to work for are exactly the kind where lots of people are genuinely friends, where they do group activities (voluntary, of course) together outside of work, and where people actually like and enjoy each other.
Likewise with the company I've founded... when the day comes that we have employees and all that jazz, I do care about "cultural fit" and I would prefer to bring in people who want to be in that kind of environment. It has nothing to do with wanting to control anyone's "outside of work" life, or denying them "separation of work and personal", it's just that it's more fun to work in that kind of environment and also, IMO, more productive.
None of this implies that we would ever demand that someone sacrifice elements of their personal life in favour of doing things with co-workers, of course. And we would not be doing group events where participation is mandatory or where you would be "dinged" for choosing not to go. It's just that I like working in a very collegial, friendly, inviting culture where people genuinely enjoy each other.
'when the day comes that we have employees and all that jazz, I do care about "cultural fit" and I would prefer to bring in people who want to be in that kind of environment.'
When the day came when I had to hire a few people, I didn't want to hurt my social relationship with friends in case the business turned south so I hired people a bit more removed from me socially. It's hard enough to think about firing one of them (what will they do afterwards? will they land on their feet elsewhere?), but it would be nearly impossible to fire a friend for poor performance or for anything that isn't a crime.
It's presumptuous to say so, but I think it should be said since it is good advice: you should work towards removing that separation as it will likely improve your life as a whole. I get where you're coming from - work is just how you support the enjoyable parts of your life - but it really is possible to make work also an enjoyable part of your life by working with a team you enjoy on a project that you're passionate about. It's not easy, but it's worth working towards!
"you should work towards removing that separation as it will likely improve your life as a whole"
... and possibly destroy your business. It's hard enough to fire a person, but now imagine having to fire someone you spend your off-hours with. Entangling work and personal life basically clouds your ability to view people objectively.
"work is just how you support the enjoyable parts of your life"
That's not what I'm saying. When you entangle work and personal life, you make it harder for yourself to make the hard decisions.