First, the legality varies amongst jurisdictions.
Second, it is one thing to let OP know how you feel about texting while driving; it is another to attack the OP, especially while not fully understanding any applicable underlying details.
Third, as clearly indicated by a poster who has decided to continue his normal routine, the criticism may not change any behavior at all.
First, the stupidity, and general dumbassness of texting whilst driving doesn't vary much amongst jurisdictions. There are times when it might be less risky, but it in of itself rises the risk of an accident. It's like why a 10 and 2 hand grip is recommended - it allows you to very quickly make corrective action if something crosses the car's path. Having one hand texting means you can't as quickly take such moves, and you are distracted and not giving driving your full attention.
e.g. Drinking a hot cup of coffee whilst driving is a potential hazard/danger. Doing it in the fast lane is more dangerous generally. Doing it in a slow moving traffic jam less so (but you could still jump the clutch and ding the car in front for example).
You don't need to know too many details. That won't rub with Mr Police Constable: "sorry officer, but you can't charge me with driving with undue care and attention, as you don't fully understand the applicable underlying details"...
It would affect insurance and liability in case of an accident amongst other things.
But don't get me wrong, maybe the OP needs a Digital Lifestyle Outfitters' VentMount, a new dashboard mounting case for the iPhone and iPod touch. That'd help typing