Wow that was a frustrating read. I dd not know it was quite that bad. Just to highlight one quote
they don’t just crawl a page once and then move on. Oh, no, they come back every 6 hours because lol why not. They also don’t give a single flying fuck about robots.txt, because why should they. [...] If you try to rate-limit them, they’ll just switch to other IPs all the time. If you try to block them by User Agent string, they’ll just switch to a non-bot UA string (no, really). This is literally a DDoS on the entire internet.
Signups in most platforms are quite hard. Straight up give your phone and do SMS verification, or at least give email and to register that email you will have to provide phone anyway. Captchas nowadays became so hard that even humans struggle with them and it often takes multiple attempts to get it right.