So, you can feed a wine lover a red-colored white wine. It will probably have fewer tannines than the average red wine.
But it would be plausible that, if a wine maker chooses a red sort with unusually few tannines, and a process which eliminates lots of tannines, there can be a red wine with this amount of tannines
So, the tannines ratio won't be an instant giveaway that it is a colored white wine instead of a red wine.
Then, the color of the liquid puts the connoisseurs in red wine tasting mode.