I've had the same experience.
Philosophically I think it's terrible that Cloudflare has become a middleman in a huge and important swath of the internet. As a user, it largely makes my life much worse. It limits my browser, my ability to protect myself via VPNs, etc, and I am just browsing normally, not attacking anything. Pragmatically though, as a webmaster/admin/whatever you want to call it nowadays, Cloudflare is basically a necessity. I've started putting things behind it because if I don't, 99%+ of my traffic is bots, and often bots clearly scanning for vulnerabilities (I run mostly zero PHP sites, yet my traffic logs are often filled with requests like /admin.php and /wp-admin.php and all the wordpress things, and constant crawls from clearly not search engines that download everything and use robots.txt as a guide of what to crawl rather than what not to crawl. I haven't been DDoSed yet, but I've had images and PDFs and things downloaded so many times by these things that it costs me money. For some things where I or my family are the only legitimate users, I can just firewall-cmd all IPs except my own, but even then it's maintenance work I don't want to have to do.
I've tried many of the alternatives, and they often fail even on legitimate usecases. I've been blocked more by the alternatives than I have by Cloudflare, especially that one that does a proof of work. It works about 80% of the time, but that 20% is really, really annoying to the point that when I see that scren pop up I just browse away.
It's really a disheartening state we find ourselves in. I don't think my principles/values have been tested more in the real world than the last few years.
> and use robots.txt as a guide of what to crawl rather than what not to crawl
Mental note, make sure my robots.txt files contain a few references to slowly returning pages full of almost nonsense that link back to each other endlessly…
Not complete nonsense, that would be reasonably easy to detect and ignore. Perhaps repeats of your other content with every 5th word swapped with a random one from elsewhere in the content, every 4th word randomly misspelt, every seventh word reversed, every seventh sentence reversed, add a random sprinkling of famous names (Sir John Major, Arc de Triomphe, Sarah Jane Smith, Viltvodle VI) that make little sense in context, etc. Not enough change that automatic crap detection sees it as an obvious trap, but more than enough that ingesting data from your site into any model has enough detrimental effect to token weightings to at least undo any beneficial effect it might have had otherwise.
And when setting traps like this, make sure the response is slow enough that it won't use much bandwidth, and the serving process is very lightweight, and just in case that isn't enough make sure it aborts and errors out if any load metric goes above a given level.
While I sympathise, I disagree with your stance. Cloudflare handle a large % of the Internet now because of people putting sites that, as you admitted, don't need to be behind it there.
Either I am very lucky or what I am doing has zero value to bots, because I've been running servers online for at least 15 years, and never had any issue that couldn't be solved with basic security hygiene. I use cloudflare as my DNS for some servers, but I always disable any of their paid features. To me they could go out of business tomorrow and my servers would be chugging along just fine.