The focus on a different place in the stack is really, really key, though. It's what's letting them make the kind of "the whole Internet's middle-man" play that they are.
They're positioned to have much wider reach than even AWS. You probably wouldn't put AWS in front of GCP or Azure. You might put CloudFlare in front of any of those. And once you've done that, well, they offer these other services that compete with the backend you're already using....
Their position in the stack has a great deal of market relevance, which translates to risk if they realize that potential, because they could well end up being a critical part of more of the Internet than AWS is.
It's not. AWS goes out of their way to make mixing it with other providers so expensive that no-one will do it unless they absolutely have to, because they are chasing lock-in. CloudFlare basically does the opposite—their whole thing is positioning themselves as an intermediary so they can snoop on and get a cut of the action on everyone "else's" traffic... and then cut everyone else out completely, as they bring more services to market. They are positioned like a boa constrictor, coiling around all their partners and providers that sit behind them.
They are not mainly a CDN and aren't even particularly interested in competing with other companies that are mainly CDNs, which becomes crystal clear if you ever negotiate enterprise pricing with them. The CDN's just a means to an end.
Nb. despite all that their public-pricing plans are such excellent values (though, beware, last I checked the $200/m one was the only one with any kind of SLA whatsoever, and not an impressive one) that if I were creating a start-up CloudFlare might well be the very first service I signed up for. If you're a small fish it's damn hard to justify not using them. And the coils squeeze a bit tighter....
And GCP has a CDN too. Would you use the GCP CDN in front of AWS, or vice versa? It's fairly common to see Cloudflare CDN (& WAF, etc) used in front of services hosted in AWS, GCP, Azure.
The parent is referring to concerns of a ubiquitous "man in the middle" and you are referring to SPOF. Those are two very different things. At any rate I can always choose two 2 or even 3 cloud providers for diversity against having an SPOF with AWS.