I agree, Mark. Everyone should be encouraged to practice good security and be responsible netizens. But, really, how often are people passing TIFFs that will be opened in an Adobe app that are just random files (as opposed to emails with funny pictures in them, which will be viewed)?
All we have at the moment is a proof of concept. We haven't seen any reported cases in the wild. We don't know for sure how it affects previous versions. We don't know whether this will circumvent normal security processes (AV, AM, DEP), so it's a little early to be crucifying Adobe (or anyone) for not going back more than 2.5 versions.
I felt the commentary about not looking at CS5.x was warranted as it is effectively still "current", but I'm not convinced that it needs to ba priority to look at older versions.