I'd say that very few logos are not copyrighted, with the exception of very old ones - and only then in their original form, old enough to be expired - the modern versions are derived works of the originals and the modern version has copyright protection for the differences between itself and any non-copyrighted version.
Given the huge amount of effort companies go through to create a logo and branding, I think the user is kidding themselves if they think there is no 'sweat of the brow' involved in a logo. Be that as it may, German copyright law is not the overriding copyright law of the project; instead US law in general and Florida law in specific is (since that is where the content physically resides and where the Foundation is based). In addition, users must obey the copyright law of the location in which they reside, but this does not over-ride that of the Foundation and servers' location.
US copyright law requires a minimal amount of creativity for copyright to hold - 'mechanical' copyrights do not exist under US law - but that's an easy bar to clear. Pretty much any logo will pass that test.
In addition to copyright law, of course, images on Commons must meet Foundation and Commons policies. I believe it was long established that we did not consider merely making a photo of a logo made it magically 'free' where copying that logo by non-camera means would not.
Photographs of a 3-D object bearing copyrighted design elements are not blanket prohibited under Commons policy, to the best of my knowledge, since under most cases these are not considered copyright violations. However, using such a picture as an 'end run' around bans on copyrighted logos is generally not considered acceptable, I believe (e.g. using a Coca-Cola truck bearing the prominent logo as a surrogate for the logo itself).
-Matt