if the package was classified by some legal entity or NGO as inappropriate. Some entity? That's very vague and easy to abuse. Silly example: I can create my own organization and declare any program which does not play my national anthem on startup as inappropriate, thus making your InappropriatePackagesList equal the contents of the pkgdb.
(such as ESRC...) According to the wikipedia article, it costs at least $800 to have a computer game rated by ESRC. Are you going to sponsor this and submit them games for rating?
The other two organizations (BBFC, OFLC) rate films, so they're both irrelevant for software distribution.
I, as a Fedora packager, am not willing to do research for any software I package to find if there might be any crazy rating-assigning organization in the world that would find my package inappropriate. Whatever I do, I do according to my own moral and family values. I can't be expected to be familiar with everyone else's.
Furthermore, I think that packages already contain sufficient information about the nature of their contents in their %description, even without this guideline. If you find a package with bad %description, just file a bug.