We need to start doing web blocking for non-technical reasons

Sure, but the problem is that you can’t easily block the worst actors. And automated blocking by IP or user agent is nearly pointless or counterproductive these days. It’s not entirely clear what actors this author is thinking of, but if you think you can effectively block AI harvesters, you are either kidding yourself, or committing to doing more work for this ethical ideal than is remotely worth the effort.

Isn't this fundamentally the same problem as ad blockers? Which is essentially a solved problem

Huh? Blocking senders as you surf the web based on what you want to see is a completely different problem from blocking requests to your server based on what the intent of the requester is. I can think of no way these problems are similar except in the very narrow technical sense of maintaining a blocklist and attaching it to a request cycle, which is really not the hard part of either of these problems.