They were saying all sorts of things to motivate the public as soon as the war started and before the genocidal acts began. Of course they had reason to assume that was coming due to Mein Kampf and all of Hitler's statements. The thing is if Stalin accepts peace he can play things all sorts of ways in propaganda, saying Goering is different than Hitler, hard times call for hard decisions, the peace deal preserved the Soviet people and revolution, they need to stand firm and prepare for further defensive actions to ensure there is not another invasion, etc.
Maybe? It'd be interesting to see what happens afterwards. I mean Stalin was a paranoid guy, and his popularity is going to plummet if he offers terms, more purges are going to be in order to keep his house in check and I think propaganda can only get you so far...