The Panopticon/Doctor Who, Torchwood and UNIT prefixes

From Tardis Wiki, the free Doctor Who reference

I know it's consense that we ditch Doctor Who prefixes on stories/products that have it as a prefix. (Doctor Who: The Adventure Games, et al.)

Apparently, we're also doing it for Torchwood as a prefix. (Torchwood: Outbreak)

However, what I don't understand is: why are we not removing UNIT from article pages? Why aren't we naming Extinction simply Extinction (audio anthology)?