Well, MTV approached The End, not vice versa, so I don't think it's some ploy by The End to make extra money. Having read what someone from Agalloch stated on the subject, it seems they're just happy to get their music out into the open.
As for the other point of this post [ie: whether or not to celebrate the enlarging of our favourtie band's fanbase], there are a few ways to look at it. Yes, it is selfish to want to hold a band back, but everyone has a certain memory [or more] that are associated with music and are deeply personal. These memories run the emotional gamut from elation to depression, but regardless, they are ours. They belond to us. Hence, it's natural to feel a more personal connection with the music that was there during said moment. For all of those special moments, one may feel as though he/she went through an entirely unique experience. But, if someone listens to the same exact thing it's possible that said unique experience could become jeopardized. Some people would deem this "elitism" or whatever, but it's really much more simple than that. If you experience the exact same thing as someone else, your experience will always be [better] or [worse] or [insert descriptive term here]. It's just human nature. To think that someone could feel the exact same as you... its a hard concept to fathom.
I mean, everyone wants to keep his/her own little secret. I wish nothing more than total success and popularity for my favorite bands, but I will always feel that the solo in Serenity Painted Death was written just for me, nevermind the amount of fans Opeth has. Call me childish. Call me stupid. But, that's how I feel, and as such, I can see why someone would be afraid to share his/her favorite toy.
I don't know if any of this makes sense, as my thoughts are scrambled at the moment, but I hope my point came across.