Why shouldn't it be? I cant take my black hole gear into a warzone without being uncompetitive so why should PvPers be allowed to take their BM/WH/EWH into a flashpoint or operation and do fine with it?
A full set of Black Hole / Campaign gear is better than Recruit gear in PvP. So you can take your high-end PvE gear and be competitive. Not against a War Hero player, surely, but it will get you a leg up to grind out your War Hero stuff.
Just like the Battlemaster geared player is going to be in trouble in HM EC, but can make it through HM FPs no problem.
There's actually a parity there.