Can you explain why it's a bad idea to be able to turn off secrecy? Sometimes I need to move a large file over the network, and the contents of that file are public (e.g. several TB of data published by the government). I don't care if someone sees this data, or even if they see me moving it, but I don't want anyone messing with it, thus I still need integrity. Of course I can move it with 'netcat' and then verify using sha1sum, but it'd sure be convenient if the default OS tools (ie OpenSSH) let me do this with a suitable incantation.
No-one is asking for this to be the default of course, but why can't we have it as an option without hacking the code?