"I don't understand why people like it" is very different from "so many folks think large swaths of the Internet should be reliant on a single company". Take Chrome browser; it's fine to use FireFox because you think it's better, it's fine to use FireFox even though you think it isn't as good but you'll take the mild inconvenience on the principle that the internet shouldn't be dependent on a single company. It's also fine to use Chrome because you think it's better, but nobody - absolutely nobody, anywhere, ever[1] - who chooses Chrome does so because they think the internet should be reliant on a single company for a web browser and they want to support making that happen.
"I don't use Chrome, I don't know why everyone thinks the internet should depend on Google" is a strawman because nobody does think that; many people use Chrome despite thinking the exact opposite of that, even. Same with CloudFlare, it's free, it's convenient, it's very good at what it does (current outage excepted), it's widely known, easy to work with, has good support. Nobody who chooses it does so because they want to hand internet control to a single company. And "I don't know why people use (popular, well known, well made solution)" is a very common internet comment which communicates a certain message.
[1] people who work for Google are paid to think that, so their decision doesn't count.
You're right in the literal sense, but I don't think they meant that literally (maybe they did, who knows).
I personally haven't seen anyone praise the Internet being reliant on a single company. However, I have seen lots of praise for Cloudflare over the years and "naysayers" (such as people raising concerns about them MITMing half the Internet) being aggressively downvoted. In that context, I see it as many people tacitly endorsing Cloudflare and not caring about the control it holds, rather than people explicitly saying "Cloudflare _should_ control the majority of the Internet."