Championship boxing is over 12 rounds. It doesn't matter who is up on the cards when a knockout occurs. It could occur at 2:59 of round 12 and it counts the same as a knockout in round 1. If you honestly think there should be an apology from Stevenson or a rematch, then you deserve to be banned on the grounds of idiocy. You're harping on about a hypothetical situation.
Stevenson is done. Also, what is the point of a rematch. After the first two rounds it was a one sided beat down and Gvodsyk finished him. At 41 years old and losing as badly as he did Stevenson needs to call it a day and retire.