My understanding is that many of the torque specs are for the screws themselves. Going above the spec risks damage to the threads. People talk about torque specs on their stems and seatpost clamps, etc.. and refer to these ratings as guidelines to avoid damage to the clamped items (ie. the handlebars and seatpost). However the obvious problem with this theory is that the seatpost clamp maker and stem maker, have no idea what model, material or make of item you're going to be clamping -- CF, Alloy, Stainless Steel, and build/wall thickness, etc..

The torque values are to prevent you irreparably damaging the actual threads of the screw/bolt itself.