See the link. It claims natives were taken to be sold as slaves during the Alonso de Hojeda expedition.
I have no idea if it is true - but in view of the “seriousness of the charge” the name of the two continents will have to changed.
https://www.thoughtco.com/amerigo-vespucci-explorer-and-navigator-2136430
Thanks; still insufficient to call him a “slaveowner” (as they may well have belonged to whoever funded the expedition - and since he was joining someone else’s expedition, I’ll assume he didn’t fund it himself). But you’re probably right: In view of the seriousness of the charge...