People don't like Cloudflare, I assume, because it's concentrating your data into one channel. They have control much like a lot of major data centers. So it's 6 of this, half dozen of the other, and those idiosyncrasies are justified differently by different selfhosters. I would hazard a guess that all major banking institutions use Cloudflare. It's just that ubiquitous. I use Cloudflare Tunnels/Zero Trust and I absolutely love it. Cloudflare is unavoidable on the internet.

ETA: To answer your question directly, yes lemmy.world does employ Cloudflare.