Really, honor has little place in PvP, unless you appreciate a challenge and the posterity of being an honorable duelist.
Aforementioned point aside, it's totally unfair to strip buffs in PvP. Why?
Because in the meta levels, stripping buffs effectively renders that 60 FTH/ 30 ATT investment useless, which is the equivalent of de-leveling your opponent.
Look, if you built a caster, and you can't cast, then you're effectively useless. There isn't any consumable item that removes armor and weapons, so there really is no anti-melee counter equivalent to the Dual charm.
So is the use of a Dual Charm dishonorable? I'd say it's about as dishonorable as the de-leveling gaze of the Irythil Jailers. It fulfills a similar purpose in nullifying a stat investment. And if you built for buffing, well...
...You just lost 70+ levels to a consumable item that required no stat investment to utilize. Suddenly, it's a match between a SL 120 quality build, and a SL 50 caster.