Because authenticity matters today even more so. A simple observation, imagine this post was purely generated/optimized by llm, it wouldn't have gotten people discussing about it. Cause it's easy for smart people to quickly notice the slop and the tone. You definitely have noticed that llms don't seem to have strong opinions, it always tries to be politically correct and that's easy to spot. But having strong opinions itself isn't necessarily a sign of authenticity though. As "itsalwaysgood" put it, authenticity forces people to think through what they want to communicate so it works as a friction for good writing and drives genuine engagement. I mean who would love the idea of talking/arguing with a bot.

When I'm talking to a person irl or even chatting online I would find it very weird if the the person is always conforming to me and rarely brings up a new genuine insight or a contrary thought to add to the discussion. I'm not looking for a debate always though, sometimes just listening to someone is enough. But I hope you understand what I mean here.