The word “tinto” originates from the Latin word “tinctus” which means “dyed”, “stained” or “tinted”. The answer also relates to how red wine is made; the skins of red grapes tint the white must until it turns into a red colour, therefore it is a “tinted”, dark-coloured wine rather than just a “red” wine. If you look up the word “tinto” in the Royal Spanish Academy’s Dictionary “Real Academia Española” you will see that the definition of “tinto” is: “El de color muy oscuro” – “Of a very dark color”.
There is no reference to the red wine name in Spanish regarding its color but to the ability of the uva tinta (tinta grape) to dye. In any case, if the Spanish language called the dark wine by its color, it would be black wine, as it's called in Catalan: vi negre.
On the contrary, there are many color references that come from the tinto wine color, such as wine color, borravino, or from the place of origin, bordó.
Anyway, a couple of things to consider:
It is always good to question the true origin of the word, if the original name had been red wine, which is not the case, it would be good to ask why Spanish does not use the same term.
On the other side, in reference to colors, not all languages have the same entries: an Eskimo has several terms for white and blue while a Saharawi does not, only has terms for ocher, orange, and sand colors. Latin languages, especially Italian, Spanish and Portuguese have many terms to define colors as a result of aesthetics, basically for hair dye. Azabache, rubio, ceniza, caoba, castaño, words that in some cases English only translates into a single term. As an example, the three names mentioned in reference to wine: wine color, bordó or borravino, in English are translated as burgundy.