Western diplomats are fond of legally and neatly putting things in boxes. Kremlin tactics are quite the opposite. Russian military thinking doesn't see a clean breakdown between what are weapons of war and what are civilian tools, or what are propaganda forums and what are channels for frank talks. The diplomats and talks are part of the offensive.
The most serious challenge to the nuclear deal may be that it does not at all address the human rights record of the Tehran theocracy or statements challenging the legitimacy of Israel. However, from the perspective of the Obama Administration and most U.S. allies, the nuclear deal is seen as a first step in empowering a more progressive trend with Iran.