The file browser looks to be based in /home for some reason. You can add a symlink to the memory card in there, which will give you access, but it does seem an overly complicated way of doing it.

It doesn't look to be a known bug (or not a reported one anyway) - there's nothing in the garage bug tracker, or in bugzilla (and why there's two separate bug trackers for it is a whole different issue). Perhaps you should file it in one of them (the packages page points to the garage tracker, so that would seem to be the preferred one).

As for whether it should have made it into extras - probably not. Having said that, I don't think the bug is serious enough to actively demote it now it has reached there.