For years now we've been in an arms race with someone using a botnet to scrape all of the account information for a particular county. My client doesn't care so much about the data; it's the server load that's a problem. Normal activity for this site is a few dozen account searches per minute, but when the botnet gets through our blockade it sends hundreds of search requests per second, overwhelmimg the site. The operator of the botnet has NEVER tried to contact my client to ask for an efficient api to access the data, which they'd probably provide for a minimal fee.
Data hosting isn't free, even if the data is.