While I agree that he shouldn't have come back, this won't stain him at all. While it would've been cool to retire never having been KO'd, it's such a minor accomplishment in a sea of greatness.
It's actually probably better that it happened this way. A close split decision or something like that may have tempted him to come back. The finality of this, getting punch out of the ring by a guy you would've clowned 3-4 years ago just confirms it.
Also, I don't EVER take what someone says after getting clobbered like that seriously. Hopkins can say what he'd like immediately after in the ring and getting punched out like that, but once he watches the tape he'll know what happened, whether he admits it publicly or not.
Now it only Roy stops taking fights and they could both go in the hall together, that would be kind of cool.