Those are guesses/assumptive though; is there anyone who knows for sure?
Many games on Steam still use SecuROM; though I agree that if ArmA2 doesn't need online activation, then it shouldn't have SecuROM on Steam, but many games still install it anyway even if it's not strictly needed (e.g. some games even install it with the game demo).
So, is there anyone who actually knows if the Steam version has or does not have SecuROM?