system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5: who are these robots that reCAPTCHA protects us from?

Who are they? How does it all work? What would happen if captchas weren't there?
gpt
The robots are programs designed to crawl sites for various reasons. They are easy to create by programmers. Not having CAPTCHA can result in:

- content theft
- credentials theft via brute force attack
- being scanned for vulnerabilities
- increased server load (a script instance can load a server as much as thousands of users)

In many cases CAPTCHA as devolved into a due diligence checklist item that insipid security auditors with no technical knowledge insist upon for no real reason.