I don't know that it does. In fact, lots of people LOVE maduros. A lot of them are more approachable to some newer palates, as they can be sweeter, more "chocolate" and coffee flavors, and they appeal more to those who favor stronger flavor in things.

There have been a number of makers who have dyed and otherwise messed with leaf to get a darker color, which has caused some folks to experience discoloration of fingers and lips, which is disconcerting, and kind of gross, so that may be what has caused your impression.