How could this happen?

I wanted to clean up the table mysql.user, because there were still 
entries for hosts in it, which we don't have anymore. I wanted to type 
something like this:

DELETE FROM mysql.user WHERE host LIKE "nn.nn.nn%";

By mistake this became

DELETE FROM mysql.user WHERE user host LIKE "nn.nn.nn%";

Caused the exact opposite of what I intended, as if I had entered

DELETE FROM mysql.user WHERE host NOT LIKE "nn.nn.nn%";

Was fatal, of course. Can anyone figure out why the wrong statement made 
such a mess?

This is mariadb 10.4.14.

Greetings
Burkhard