Moreover, visible light has much more energy than microwave radiation. Light energy is a function of wavelength and certain wavelengths are required to do certain things. Microwaves correspond to the energy required to increase the vibrations and rotations of molecules, which can increase their heat. Higher energy light such as IR can increase the vibrations even more, and many objects absorb in this range, which also increases heat. Visible light is capable of inducing bond changes in extremely low-energy systems, like the extended conjugation in the pi system of retinaldehyde, where the cis/trans isomerization is the prime molecular driver of optical signals in the eye.
You don't get into the energies required to break carbon-carbon bonds until you start getting into the UV range, which is why UV light causes cancer and is so damaging. UV light can cause bond homolysis and generate radicals, which then go on and form bonds with other things, which is the primary mechanism for causing cancer. Things like X-rays and gamma rays are even more damaging, as they don't break bonds in molecules, they actually eject electrons and form ions, which can be hellaciously reactive and even more destructive.
These are the reasons that scientists tend to roll their eyes when cell phones are accused of causing cancer. Potentially, the microwaves could cause localized "hotspots" that may induce some reaction to cause cancer, but the chances are ludicrously small.