The underdark is the most hostile environement imaginable and contains every big bad from mindflayers, beholders and even dark gods like Lolth. If there was a fluffy bunny in the underdark it would monty python your aas before laying eggs in your dying body with the added bonus the eggs will keep you alive and in perpetual torment for a millennia.
The Drow call this place home sweet home. They see in the pitch darkness like a humans do in the midday sun. When the Drow come to the surface they attack in the dead of night where all you would hear is screams and torment from the pitch of night before a deathly silence. The lucky ones will have died, the unlucky ones will be dragged to the underdark to be sold as slaves or thrown in pits of spiders to be torn apart for the entertainment of the masses. These villages and towns would be found afterwards with the odd villager in acute mental trauma after seeing the mutillated bits and pieces of friends and family and whos only memory is of the screams of loved ones being hacked to pieces.
The Drow are cruel without purpose, without mercy or conscience and only live to please their respective god. The red eyes of the Drow is a blessing of Lolith to inspire fear in all races they encounter, it is their raison d'être. The Drow are at constant war with themselves and only the most ruthless survive to adulthood. Nothing good EVER follows the Drow, if someone is lucky/unlucky enough to actually see a Drow they dont hang about to find out what mood it's in. That goes for most of the "civilised" races in D&D.
So if someone sees a high elf they say hey dude hows it going? If someone sees a Drow they don't say anything, the only evidence someone was in the area would be brown stinky footprint heading literally anywhere else.
I hope this goes some way to explain the dialogue choices.
