I get your angst. The little guy unable to compete against the giant corporation. We've seen this play out for decades in every possible tech space.
The trick is to leverage your strength, not your weakness. There are advantages to being small - being creative in exploiting those advantages is the key.
In terms of AI blockers, that's not useful. In the same way that Google blockers (robots.txt) doesn't harm Google. Individual actions are meaningless in a world drowning in content.
Sure you can block your blog. But the AI has plenty of material to train on without your blog. If it makes you feel better then go ahead and block it, but don't expect that to have any real-world effect on you or it.
Most of the "new knowledge" you posit does not come from blogs. It comes from Facebook, Twitter, Wikipedia, Stack Overflow, and all the rest.
Plus, AI doesn't have "knowledge" in the way we understand it. It's a giant probability engine. It's not about "new knowledge", it's about "average knowledge".
In short, my advice is not to spend too long thinking about this. Adapt to the changing world, don't fight it.