So I cannot combine a work licensed under this license with a work licensed under GPL3 + SSL exception because the latter does not allow downgrading to gpl2 (or upgrading to gpl3+).
I think you're wrong here. Being pedantic, NO version of the GPL allows regrading. It's the "grant of licence" that allows the regrading.
Is this intentional?
No. Because the grant of licence DOES allow regrading, therefore what any particular version of the GPL says is irrelevant. The recipient CAN change the licence from GPL3 to GPL2 (or vice versa) because the *grant* gives him permission.
Cheers, Wol -- Anthony W. Youngman - anthony@thewolery.demon.co.uk