It's really easy to generate a public RSA key with desired patterns in it. The 1992-era PGP did use the last few bytes of the public key as the identifier, but

It's really easy to generate a public RSA key with desired patterns in it. The 1992-era PGP did use the last few bytes of the public key as the identifier, but later versions moved to using a truncated hash (MD5, and later SHA). At some point someone generated colliding keys for all the keys in the public keyring and uploaded them all, which kinda drove the point home. (I assume that it's harder to generate a public ECDSA key with a specific pattern, but elliptic curve stuff didn't become common until after hashes were used for key identifiers.)