I feel like it is because it's a group of people in the same field, which is constantly changing. There are topics related to the group that make sense to discuss.
With smart people, I suppose any topic is on the table. It's not specific enough for me.
It seems like most commenters are in software engineering or related jobs. But it doesn't appeal to lots of people in those fields. There are biologists and truck drivers too. And lots of people have pointed out most companies are tech companies now.
Most topics here might interest people for professional reasons. But they include things like "High IQs are associated with mental and physical disorders" too. People love to debate politics. And "Is the Ship Still Stuck?"[1] is the top article right now.
With smart people, I suppose any topic is on the table. It's not specific enough for me.