Beer (wort, at this stage) is heated before fermentation, normally not boiled but enough to kill bacteria.

Wine is normally made from pure juice, and isn't heated at any point in the process. But again, it's made from pure juice: the inside of a grape is not a usual place to find dangerous bacteria, and on the outside one would normally find only the yeasts which produce the fermentation.

Modern wine-making washes the grapes thoroughly and adds yeast, the old-school method was simply to crush, and rely on the surface bloom and residual yeast in the vessel to do the work. Which lead to rather more vinegar than the modern vintner would tolerate.