Maybe they are not anti-social, they are just not being social to you! They have no obligation to entertain you even if your kids are playing together.
This is a really cynical and negative way to view basic human interaction, the cornerstone of our species and civilization. I've been seeing it a lot lately online, and it doesn't surprise me that people are lonely and aren't making friends if they adopt an attitude like that.
If you go up to a fellow parent and say, "Hey, nice to see you again." and they just ignore you scrolling their phones, sure, they have a Constitutional right to do that and are under no obligation to return the greeting. But going through life only doing what you are "obligated" to do seems like a very miserable and anti-social way to live.
If you don’t want to be social go live in a cabin out in the woods.
Obviously this doesn't apply to everyone, but as someone who suffers from social anxiety, talking to someone I don't know very well absolutely does cost me.
That said, I do try to be nice despite the anxiety it causes me, and if someone came up to me and said something to me I probably would respond. But I certainly wouldn't go approach someone else.
It's also a very Hacker News attitude, as you are witnessing in this thread.
I don't understand why people HN talk down about Reddit so much when it's really no better here, either.
Once someone points out that they like going to the office because they get to socialize with co-workers, the replies typically sound like ‘don’t care, I’m not paid to socialize but to do my job’
While I understand the context can vary, it always struck me as an anti-social behavior.