Why does scp have an exit status of 0 after an error message?

Question

On Linux or Cygwin, I get the following (note the invalid location in the username):

>scp file.txt "invalid [e-mail]:file.txt"
invalid user: invalid user name
>echo $?
0

Why is exit status 0?

Note. I know a well-known error related to scp failure, but in the above case the error is printed in stderr.

Answer 1

An error. I informed him.