I would agree with everything Doug mentioned. I make some very fruity
higher acid wines from North Eastern fruit such as Catawba, Cayuga etc
along with other hybrids. If you don't sweeten them they are just too
unbalanced as to acid to be pleasant. They are just better with some
sweetness. Those are good anytime. Desert wines are often used at the
end of the meal although anyone who tells you there are hard and fast
rules about wines and pairings just does not realize the breadth of the
subject.

Personal preferences often change with time. I do remember liking
Lambrusco when I was much younger. I'm not sure anyone will ever
convince me I need to make it for myself now though. There is a
natural progression with wines where new wine drinkers prefer sweet to
begin with then progress to simple whites, then more complex dry whites
and then the same gamut with reds, from lighter to more full bodied.

I would say dessert wines don't actually fit into that progression;
most people like at least one type or another and always do. I like
cream sherry but not port. Go figure.

Some dessert wines have had alcohol added to them to prevent
fermentation, a high proof alcohol is used to stop the fermentation.
They are very stable at that point. The idea is to get the alcohol
above the point the yeast tolerate.

Joe