Somehow I doubt that the opinion of Putin is taken into great account at the moment in the Western world. The fact is that both the EU and the US have motives of their own to support this agreement and some of them are actually against the interests of Russia (lifting the embargo on oil and gas, most obviously).
Truth be told, a big part of the reasoning behind the Western support of this agreement is probably to slowly pry Iran away from the Russian orbit.
At the end of the day Iran is the backbone of the Russian alliance system in the Middle East and if we can pry them away then we can neutralize Russian influence in the region to a great extent.
