But why do you only point to Alamy, there are lots of images that appear in the result. There's facebook, X, github, and Pinterest and there's even tiktok. Does it mean those keys are also on those websites?

I doubt there is truth to this post. I have kept my private key somewhere safe, I created a wallet that has never been used but only deposit transactions I'm sure there will be nothing of public key that is exposed by it. How will the wallet keys be exposed with that security in mind?  This is just something for that meduim page, fud for the crypto holders.