No. Him having being beaten by Rocky, who was smaller than Usyk, shouldn’t have a bearing on anyone’s opinion.
I think you might want research Moore’s record a little more. He had plenty of experience with southpaws both as a pro and as an amateur.
I’m not saying Moore would win, but he literally has 6 times the knockouts that Usyk has professional fights. Hell, isn’t Moore’s career longer than Usyk’s entire life? I think this is a helluva mythical matchup, pitting a legitimate, no-questions-asked top 10 ATG against a modern, presumably ATG. Both men have some advantages over the other, and neither man has ever seen a comparable opponent like the other before. And both men are known for being complete class acts in and out of the ring.
Just to name a few Bert Lytell, Bandit Romero, Tabby Romero, and Alabama Kid. If you dig through his record you’ll find others. Archie also fought plenty of switch-hitters. A few examples being Clarence Henry and Frankie Daniels.
They aren't as skilled as Usyk, at least not to my knowledge, but it does show Moore can hypothetically beat a good southpaw
Moore was a very good fighter but Usyk is too big, too fast and too smart. Usyk wins every round and eventually knocks him out or wins by wide decision. The talent gap is too wide.
While amateur fights and pro fights are not equivalent, surely the fact that Usyk had 350 am fights, of which he won 335, counts for SOMETHING. Was Usyk ever a LHW? If so Moore wins a decision. At CW the odds would maybe be 60/40 in Usyks favor. At HW Usyk wins a decision. Too big, too fast, too strong. Remember a slow 186 pound Marciano wrecked Archie.
Easy to say that though. Usyk has never seen a Moore before, and he could barely beat Mairis Breidis.