Because people do things like this. They spin up OpenClaw and ask it "find me a computer with an RTX 5070Ti or 5080 that's in stock within 50 miles of me that I can go and pick up today".

So now the agent is crawling bestbuy.com, walmart.com, etc looking for PCs. I don't run one of these sites but I would bet the traffic looks a lot like a Web crawler and is incredibly resource-wasteful. If you were at the screen you might go and start searching for "5080" or you might go into Computers and start filtering. People just don't care if an automated agent is wasting someone else's resources.

Also, where's the ad revenue in an agent crawling your site?

It's just going to be an arms race like adblockers and CAPTCHA but it's going to be so much worse for real people who want to do anything.