You misunderstood. It says some of them celebrate that their child will have the opportunity to be a part of their community and culture. From what they've experienced, they can see it'd be a profound shame if their child isn't able to participate in something they've had so much positive experience from. Though that's not universally true. Also a child growing up hearing with deaf parents will have a whole set of problems that they would find challenging to meet, and could fear not being able to help.
On top of that, cochlear implants are not miracle devices, and as I understand it, deaf children who get it will still have significant hearing and speech issues and may end up isolated from both sides.