I'd hope that by being inclusive in my response and recognizing trends that exist, we could be all inclusive without having to resort to any claims of "assumed basis of discussion".
That being said, I don't agree with you at all that discussion is "4e unless spelled out otherwise". If you wish your discussion to be about 4e, then it's probably best to say so. They've provided tags for just this purpose.
My point wasn't that discussion of any other edition is somehow "inferior." But in a discussion about
any topic where multiple versions exist, if someone doesn't say otherwise, it's a reasonable assumption to make that they're speaking of the current version.
Right now, there's only one edition of D&D
currently being published. If someone asks me a question "about D&D"
and doesn't specify an edition, I tend to assume they're speaking of the current one. That's not a value judgment in any way; just a common starting ground.
If someone asks "Are priests and clerics the same thing in D&D?" the default answer is "no," because
as the game is currently being written, they are not. If they specify the question to prior editions--or if that fact changes in
future editions--obviously the answer no longer applies.
It would be the same as if someone asked "Is Dave Arneson a D&D writer?" Well, no, he's not. He
was, and I am in no way disparaging his contribution to the game's history--it wouldn't exist without him, and I'm grateful--but that doesn't change the fact that
at the present time in the game's current incarnation, he is not a D&D writer.