I don't know their reasons, but for me, I do use cloudflare, but only in a way that I have a transfer-off plan.
So far as I can tell, Cloudflare seems to still be in the early stages of enshittification [1], and while I as a business customer am probably going to be taken for a ride later than most customers, I'm also small fry, so I'm guessing at some point in the next 5 years, some of the "for free" features like zero trust / tunnels are going to become prohibitively expensive for me.
I assume Cloudflare will enshittify because too much of its services are free or too cheap to make sense, so my guess is they're trying to achieve massive market capture and dependency so they can later start squeezing customers for way more money.
I prefer more transparent cost structures, like what I get through Migadu for example.
Cloudflare isn't even that big. They're 1/100th the size of Google or MS. They're not even the biggest CDN—Akamai has twice the revenue, but it depends on what you measure. Cloudflare gets brought up disproportionately often on HN because they have generous free tiers and cater to indie hackers more. So it feels a little ironic that they're perceived as "the big dog" by the indie hackers.
It feels like every website uses them as a web proxy, meaning they get to 1) decide which users can access the site using their own opaque methodology and 2) MITM/inspect a large percentage of web traffic.
