We've seen that at least some if not most of those houses are two stories tall.
That wall is tall, but it doesn't look tall enough to block the windows on a two story house. That and, light pollution is almost non existent at this point.
Think of it like being in a plane at night, you're 20-30,000 feet in the air but you can still see lights on the ground, imagine being on a hill with a semi view of Alexandria at night... Candle's don't burn as bright as a bulb and neither do lamps, you're gonna know that they have some kind of power source to their places.