Iodine is actually useless except as a coping aid. USSR had a lot already stockpiled for one of their foreign aid programs, and their leaders' in 1986 were as fake and insincere as ours today.
As to why Putin enjoys taking it like a b*tch, he's a Sub and always has been when it comes to coked-up Western leaders in fetish gear...
(Joking... I hope)