I understand your points, but both Russia and Iran are not now dominant world`s empire to argue about which onw will have the international edge...If France and Germany, mileanial enemies had to be united in international matter to stay relevant, it`s very similiar to actual Ruso-Iranian relations...They dont have too much other options or candidates for partners, and they need relevant partners...
I am not proRussian at all, but taking anti-russian position now, under actual conditions is not very helpful in this iranian fighting phase...