Huh? I just didn't understand what the community part of your suggestion has to do with anything. As I pointed out, picking a "purged" username is not the same as choosing username that has never existed, and that that username still needs extra work before it is ready to be used again, for communities and regular accounts alike. And I don't see why this ought to happen to every "purged" account, i.e. with the purging rather than the reusing. It makes sense to only go through the trouble if someone else wants to use that name, whereas the majority of purged names is not of any interest to anyone so there is no need for that work.