Question

Why was wine adopted as a ritual drink in
Christianity, but Islam prohibited the use of alcohol?

Answer 1

I have no idea, but I can speculate.

First, and most obviously, grapes were actually grown and wide made in the Greco-Roman regions of the Mediterranean where Christianity first spread -- indeed, wine and winemaking were very important parts of Roman Empire tradition in the first century AD. On the other hand, grapes do not grow in Mecca or Baghdad, and wine had to be imported from Aramaic and Syrian traders. Wine was simply not part of the culture that birthed Islam, the way it was part of the culture that birthed Christianity.

Second, Islam was founded in the 600s in no small part as a rebellion against the domination of Christianity, particularly the powerful established Roman church in the East. It's hardly surprising that the earliest Islamic zealots would have rejected this particularly Roman aspect of Christianity.

Third, Catholicism and Islam are distinct theologically: Catholicism is a religion that stresses that even sinners can be redeemed, if they truly believe. Good works and purity are less important than true faith and sincerity. This is why you can be Saved even if you are a murderer and you repent at the hour of your death. On the other hand, Islam, like the more evangelical branches of Protestant Christianity (which sprang up still later, in the 1500s), emphasizes the quality of the Saved. Good works and personal purity matter quite a lot -- in fact, they may matter more than faith. You might be saved even if you DON'T believe, provided you have led a blameless and exemplary life. From this point of view, it's not surprising that Islam would have laid much more heavy emphasis on personal purity -- including e.g. abstinence from drinking, smoking, sex during menstruation (indeed, any contact between the sexes at that time), the ritual praying, self-punishment, et cetera. (Some of these also come out of Jewish tradition, too.) You can certainly find among Protestant Christianity today sects that are just as adamant about refraining from alcohol as the Muslims, e.g. the Seventh Day Adventists.

Finally, and perhaps not as trivially as it seems, the core ritual of Christianity has always been the re-enactment of the Last Supper (the Eucharist), at which, in fact, bread was broken and wine drunk, and it was probably never really thinkable that this central ritual would be drastically reformed, e.g. by omitting the wine, once it was well established. Religions rituals change very, very slowly. It was only in the mid-20th century that the Catholics stopped saying Mass in Medieval Latin.