[quote]It's just irresponsible for the package maintainers to come back and say "we can't pull it, we're leaving it as is, and we're not patching it either".[/quote]
The package maintainers didn't say that. This package is in the universe repository. The entire purpose of this repository is that volunteers can upload packages that Canonical has decided they aren't going to support. So Canonical isn't the package maintainer and you can't really blame them for not supporting packages that they said they aren't going to support.
Furthermore, it sounds like the ownCloud developers want Ubuntu to either use the latest & greatest release, or remove the package entirely. If that is correct, then I think it is irresponsible on the developer's part. Version 7 only came out 3 months ago, so they really ought to be providing security patches for version 6.