How did the Arabic word "alcohol" come into usage in Europe rather than the Latin word "vocatus?"

Words very often get tied to a new technology or skill. So they learn the name of the technology in the source language.

Alcohol in Arabic (al kuhul) referred broadly to the process of distillation in any form, including eyeshadow or any fine powder. This is true into the 18th century. So it didn't refer to exclusively to the beverage until very late.

The other half of the story is that the Greeks and Romans fermented, but they didn't distill. So when the skill of distillation spread, it used the Arabic word and the outcome was referred to as alcohol. And since the word 'alcohol' applied not just to the liquid product, but the process by which the liquid product was achieved, it was going to stick.

Eventually the word was then applied to a specific chemical compound that became known as 'alcohol'. And since that compound is found in beer and wine as well, they became known as alcoholic beverages too.

So basically you can thank science for that one.