lol guys, the expression is "moot point," not mute.
Anyway grass decks that include Sceptile and/or Tangrowth SF (and no I don't need to be told that this card is "Tier 3" or whatever-- it does exist and it will be seen) both have valuable anti-Dusknoir options in the form of Poison. Sceptile GE can't inflict it, but a teched SF version certainly can. It followed by Slice Drain will lead to a poison KO at the end of the Dusknoir player's turn (following that 2nd attack obviously) if it was undamaged and hadn't retreated/Warped etc.. Slice Drain also conveniently heals 2 damage counters, which effectively negates a round of Ectoplasm. GE Grovyle can also inflict poison. Tangrowth has the added benefit of Green Heal, which also negates Ectoplasm after each turn.
Torterra/Sceptile also has the ability to shrug off Ectoplasm with the DP turtle.
I think this is what Brady1 meant when he said most grass decks have the ability to beat Dusknoir. Perhaps I'm wrong.