you see, there are many advantages for getting a CI. with a CI, life is easier, in terms of adjusting to the rest of the dominant hearing world by learning how to speak and listen. i wouldn't say that getting a CI destroys the deaf culture, because essentially, you are still deaf with a CI or not.
those who were raised with ASL as their primary mode of communication end up attending deaf schools where their education sucks, since the deaf students tend to be very behind academically, especially in reading and writing. i mean, look at how ASL people write--with poor grammar. those deaf people don't get very far in life, in terms of their education after high school. they usually get lousy jobs.
so i believe that with a CI, you have more and better opportunities availible to you. i know for some people, it doesn't work out, but for others, it does and those people usually end up being mainstreamed in schools and performing academically up to their hearing peers. this leads to them going to college and getting decent jobs after high school.
inevitably, the deaf culture is changing and those deaf people need to learn to accept CI users into their culture, rather than bash on them.