I have tried renaming textColor various names but always populates Fallback Text. I think it has something to do with the space between Text and Color.
Interesting find. I just replicated with mapping data onto a Tags component and can confirm that even with the property set to textColor the component seems to not pick it up automatically to fill in the Text color input field.
I can file a bug report to have it look to find camel cased textColor so that you won't need custom strings with "text color" or any variation on that!