Their biggest seller though, Original Spiced Gold is according to themselves "a blend of rum and other spirits".
"Other spirits" is an industry euphemism for Grain Neutral Spirits, i.e. industrial alcohol produced using the cheapest base and distilled to 95%, which is something you then buy in bulk. Take a look at these guys, for example: https://ultrapure-usa.com/grain-neutral-spirits-options-sign...
Or take a look at this page: https://ultrapure-usa.com/services-2/spirits-brand-owners/ Want to launch a Gin company? Rum? Whisky? They're experts at white-labeling!
Yes, you have to read between the lines to understand how this works, because none of the large alcohol brands wants consumers to know how their products are actually made, it's all obscured by deceptive labeling.
Also, at the end of the day, ethanol is ethanol. The difference between Captain Morgan's Original Spiced Gold and actual Jamaican rum is like the difference between synthetic diamonds and real diamonds. Yes, both are 100% carbon in a diamond lattice with the exact same refraction index and hardness and properties. They sparkle the same, they look the same, only experts can tell the difference, but a lot of people still care about the difference.