I think the big issue here is that you need to be part of the 'in crowd' to know that the DSA team is reached via the debian-admin list. It's not logical, IMHO, for these to be related. I don't believe that these two teams completely ignore the debian-security lists, as they obviously(IMHO) have stake in the security aspect of Debian.
There is likely and should be a few ppl, not necessarily members, watching debian-security that could forward on an FYI to these teams. I don't think it's right to try and teach EVERYONE the layout of the land, instead such postings should be forwarded to the correct team without needing to involve the individual "trying to help" with the local and internal politics.
I say this only because it's logical to outsiders that these teams be reachable here and thus they should be, even if they are not.
Cheers.