Presently, we don't know what happened to Air France 447. We have no need to speculate. We do know, however, that airplanes are not raining down on a daily basis, failing in turbulence. Failures in turbulence are rare. They do occur.
There is a big difference between encountering a little turbulence enroute, and flying through a thunderstorm.
In flight, we take great pains to avoid thunderstorms, flying well around them, above them, or using routing that will keep us clear of weather. We have radar which allows us to see not only where the weather is, but its intensity.
I have been in turbulent conditions so great that on one occasion the flight engineer in the aircraft directly behind me was ejected from his seat, bounced of the ceiling in the cockpit twice, and ended up downstairs in the cargo area (a Lockheed C-130). We were at low level in strong winds on the lee side of a mountain, and the turbulence was violent enough that we couldn't see the instrument panel clearly. I've been in severe or extreme turbulence like that during low level activity in the mountains on hundreds of occasions while fighting wildland fires from the air in airplanes...and experienced a grand total of one occasion when we found a structural crack (which we later repaired).
Such occasions are virtually never experienced by passenger aircraft in airline operations. I've operated airplanes which spent nearly their entire lives operating in such conditions, whereas a passenger aircraft may go decades and tens of thousands of hours without ever encountering such conditions. (as a comparison, a NASA study found that we encountered such condition at a rate 500 to 1,000 times that encountered in commercial operations, during a fatigue study of our aircraft). It would take a commercial airliner 200,000 hours of flying to come close to ever encountering that kind of turbulence, and enough of it, statistically, to even begin to approach that kind of exposure...and even then the airframes are typically designed to be able to stand up to the abuse. In practical application, it's a very, very rare thing to be exposed to any level of turbulence remotely close to hazardous, in commercial airline operations.
There has been much speculation made of what happened to the Air France flight. This is nonsensical speculation; we don't know. Until the investigation is complete, the fearmongering and posturing about what *might* have happened has no basis or ground in reality. You're safe when flying from A to B. Don't let the armchair experts out there tell you differently.
From a pilot's perspective, think of it from my point of view. From my office in the airplane, I'm the first one to the scene of the crash. You don't really think I'm going to let that happen, do you?