Have you asked yourself how they can make everything free? What are their incentives? When they successfully centralized majority of DNS resolving, what could they do with that power? Keep in mind that even if their motives are pure at the moment, management and ownership of companies can change.

Look a few years back and you’ll find similar enthusiastic comments about Google: they make everything better and for free. Everyone should use their search, everyone should move to GMail, etc.

Good points. As others have said, I'll probably move off later on, but for now I intend to stay with them (similarly I've been with Gmail for a while and now moved off to stuff like Fastmail, hosting my own "dropbox", etc.).

Primarily because for beginners it's a bit easier to setup everything without much hassle.

I found running the bash script to set up Let's Encrypt on a Digital Ocean box honestly easier than navigating through Cloudflare's admin web UI.

I think it was certbot that was recommended by DO to use; I used certbot and it was super easy to setup, but at the moment I feel that Cloudflare's security, fast delivery, and analytics will keep me onboard until I can self host/do myself when I have a good amount of time.

...as long as the target isn't getting too much negative exposure, and when this will happen (it will), they will happily block that resource.

Good point. I think they crossed a line when they shut down controversial sites, which they shouldn't have, but at the same time it's easier for beginners to start out with everything.

Well, it's not really free, government is funded using our tax money, but I get your point.