When more people consume bandwidth, more bandwidth has to be purchased by the ISP to increase capacity for the collective need. Otherwise, the existing connection becomes over-utilized and downloads slow down for everyone using that ISP.
Routers have processors that consume more energy when under higher demand. They also generate more heat when utilization is higher, which must be mitigated with cooling systems, also consuming more power. This factor might be small on your home network or even for a small or medium sized business, but it adds up when racks upon racks of networking equipment are being considered.
Power and real-time bandwidth (not what you download per month, what bandwidth is being used right now) cost money. That cost is passed to the consumer. Thinking of bandwidth as being like roll-over minutes that you need to use or you're wasting something is a flawed consumerist notion. If you conserve, perhaps you could move to a cheaper Internet package and save some money for a rainy day or know that you aren't being a wasteful consumer.
I use less than 10 GB per month and I still have room to play on-line games almost daily, view the news, e-mail, corporate remote access and keep my home network up-to-date.
Poor use of Bit-torrent chews up more than it should. Most clients include bandwidth throttling options that could easily be used to get what you need quickly and then control how fast you are going to seed what you've already downloaded.
Your tag line is bizarre, senseless and revolting. "Patriotism is bigotry" How cute. Did your Bohemian friends at Columbia teach you that one? Such ideas are why nations that still embrace patriotism or any level of national pride are going to destroy us economically, if not in other ways. When the U.S. looks like the 3rd world places I have to work in perhaps you'll understand why you should care about your nation, regardless of which nation you belong to.