As far as I see it, there are three main alternatives here:

A. Write the default fluff in the "old" way: All Orcs the PCs encountered can be killed without hesitation, because they're orcs.

B. Write the default fluff in the "new" way: Orcs are people and should be treated as such. If it means lessening some of the game's Hack-and-Slash tone, so be it.

C. Ignore the issue entirely: Don't write fluff about this at all and let each DM decide that for themselves.


Personally speaking, I find B and C vastly preferable to A.