1.5.1/1.5.2 run from the NEWEST LAUNCHER on Retina macs is all blurred

While the new launcher itself is now capable of being displayed very clearly on a retina display, OLDER versions of the minecraft .jar being run from it on a retina display are blurred.

Selecting "Release 1.5.1" or "Release 1.5.2" from the newest MinecraftDev.app launcher launches the game in a blurred state - all text is blurred and apparently pixel-doubled?
Selecting any of the 1.6 snapshots however, shows no signs of problem.

The old launcher does not blur 1.5.1 or prior versions on retina macs - it displays correctly.