In some respects, they are right, but I ultimately see this as a bad move.
The way I see it (and I have been a cell phone user for years) is that the phones don't bring anything into your life that you don't explicitly go looking for in the first place. I have never received a call from a sex service or from any other immoral business. The only way these phones can be used for immoral activity is if the owner goes looking for it (for example, by dialing the number of a phone-sex service.)
I would like to believe that the people buying the kosher phones could be trusted to not go looking for immorality without requiring a board of rabbis to tell them what numbers can and can not be dialed. And if a person considers himself unable to avoid this kind of immorality, why would he buy the kosher phone in the first place? To show off to the neighbors? (Actually, maybe there is some truth to that...)
Now, it might make sense of these families are buying the phones for their children. Kids sometimes go looking for immoral content, either out of curiosity or as a form of rebellion against their parents. In my opinion, however, blocking systems like this are a meaningless façade. Sure, a kid with a kosher phone won't be able to dial a sex line. But if he is rebellious, he will simply find a different avenue for his rebellion - like buying pornographic magazines, or getting his own phone that his parents don't know about. Technology may be able to make immorality inconvenient, but it can not do a thing about what's in a person's head.
A better concept
All this being said, I think there is a place for a "kosher phone", but not the device Mirs is selling today.
My kosher phone would be based on a modern cell phone, with all the bells and whistles. It would have a camera, text messaging, video service, etc. It would also come with an array of Jewish features to make use of this technology. For instance:
- An address book pre-loaded with "dial-a-shiur" services, so you can learn Torah from anywhere at any time.
- A similar feature using text messages - a daily mini-drash that can be delivered automatically into the phone (or e-mail box) every morning.
- Torah-study chat-rooms, where Torah is discussed 24 hours a day by whoever wants to connect. (Moderated by rabbis, of course, to prevent the discussions from straying too far off-topic.) This could be text, voice or video.
- A calendar pre-loaded with the Jewish holidays, yahrtzeit-tracking capability, and software to compute the times for prayer, fasts, etc.
Note that none of this involves blocking anything. It trusts the owners to actually practice the morality they preach if they want to keep objectionable content off of the phone. I think that most people can be trusted with this responsibility, and those that can't be trusted have problems that a restricted phone won't cure.
As the Lubavitcher Rebbe said on many occasions, technology is not something that should be avoided or banned. It is something that should be made holy by using it for kosher purposes.