The reason it is illegal in these jurisdictions is the relatively high alcohol content by volume of this brew, 27 %. (slaw.ca)
While it is hard to taste the alcohol mixed in with all the fruit juice, those drinks can contain high alcohol content, not to mention tons of calories and sugar. (travelandleisure.com)
Warmer, longer growing seasons have allowed grapes to stay on the vine longer, producing fruit that results in stronger, bolder wines with higher alcohol content. (sciencenews.org)