The OP doesn't recall generating one. Genuine question: do you also like it when someone else generates a key for you without telling you? Personally I would rather know about it.
They wrote in the book "me@foo.com: use key" - and then people did. If he wanted different behaviour, he could have published "someoneelse@foo.com" and then they wouldn't use it to email _him_.
Well, yes, actually, that is what I would expect. (Well, not necessarily in person, but via a different communication channel, even by unencrypted email.)
I remember when I was first playing around with PGP more than 20 years ago. The usual convention was to talk to the other party first about encrypting your messages, and not to assume that the recipient could receive and decrypt them in all circumstances.
Just blindly downloading keys from a keyserver and hoping they're the real thing was not the idea.
I do have an OpenPGP key published to the key servers, mostly for toying around with GnuPG cards, but as soon as anyone starts emailing me encrypted messages without any context, I’ll delete it.
It's not a security risk to read an encrypted message. Why would you delete an encrypted message?