Bug in BSD: to whom shall I report it?
It's not a bug, it's poorly written documentation. The -f option for chown states:


  Don't report any failure to change file owner or group, nor modify the exit status to reflect such failures.


This means the -f option is only applicable if the target file exists and there was an error in changing the owner or group of the file, which of course you can't do on a nonexistent file as in the OP example under macOS.

To show that the -f option actually works as intended, use the following compound command in Terminal while not doing so as root or using sudo:

touch ${TMPDIR}testfile; chown root ${TMPDIR}testfile; echo $?; rm ${TMPDIR}testfile


The output will be, e.g.:

chown: /var/folders/7l/lcvbc47n3sd7jcztdhc9c_pw0000gn/T/testfile: Operation not permitted
1


In this first form, without the -f option it fails, exits >0, because the chown command is trying to set the owner of ${TMPDIR}testfile to root while being executed not as root and not using sudo.

Now execute with the -f option:

touch ${TMPDIR}testfile; chown -f root ${TMPDIR}testfile; echo $?; rm ${TMPDIR}testfile


The output will be:

0


In this second form, with the -f option, it succeeds, exits with 0 without having made any change, because it was done not as root and not using sudo, which is necessary to change the owner of a file to root.



Note that each OSes chown is not equal in all functionality to each other. In other words, while I don't have Red Hat, as mentioned in the OP, I do have Linux Mint to compare to, and the man page in Linux Mint -f option for chown states:


  suppress most error messages


As you see most is the keyword, so it doesn't suppress all error messages in Linux Mint nor is the description of what -f does with chown under Linux Mint as detailed and explicit as under macOS.

So while in Linux Mint, not as root or using sudo, chown -f root non_existant_filename will not output an error, however, its exit code is 1, not 0 as it is with the macOS chown example above using -f within its defined context.