The Rosenbergs were true believers. They devoted their entire lives to their faith. They spied for their faith. They lied for their faith. They died for their faith. I have never questioned their courage or their integrity. They were communist heroes. I.e., heroes on the wrong side, morally no different than the devoted SS men who died in the rubble of Berlin because their Fuehrer had ordered it.
In fact, the Rosenbergs handler in Soviet intelligence was furious at American Leftist for their denial of the Rosenbergs spying.
From his perspective, the Rosenbergs were Heroes of The Soviet Union who did work of unimaginable value to the Soviet Union and deserved credit for their contributions