Craigslist makes its data publicly available. How can it be illegal to access that data? It may be against Craigslist's Terms of Service, but that means it's up

Craigslist makes its data publicly available. How can it be illegal to access that data? It may be against Craigslist's Terms of Service, but that means it's up to Craigslist to figure out how to prevent scraping. It does not mean the law needs to be involved.