(IAAL but this is not legal advice.)
It’s not libel. Defamation requires a false statement of fact. Marking a website as “unsafe” is an opinion.
Marking a website as "unsafe" in Chrome is equal to standing in front of the door of a small restaurant and blocking 71% of people going inside. Everyone first has to agree that they will enter the restaurant at their own risk.
That is more than an opinion. Chrome has a monopoly and should act accordingly. Blocking entry to a website should be a last resort, not just because someone didn't add their website to the whitelist.
This seems like a distinction without difference, given everyone in the ecosystem takes that "opinion" as true fact, including the market-leading browser produced by the "opinion"-haver.
I get that's mostly what corporate lawyers argue about, but it's functionally dishonest in this case.
I always wonder what the settlement and damages would be if google marked Amazon as a phishing site for even a few minutes.
The problem is that these gatekeepers of the internet respond to false statements of facts/opinions by so called professionals.
I had cloudflare mark a worker as phishing because a AI "security company" thought my 301 redirect to their clients website was somehow malicious. (url redirects are normal affiliate things)
If the professionals don't understand the difference and cloudflare and google blindly block things, this is scary.