Incidentally, the microwave oven was invented by accident. A scientist doing research to improve radar systems after World War II discovered that a microwave transmitter he was working with melted a chocolate bar in his coat pocket. At and above 300 GHz, you get into Infrared Radiation frequencies. The microwaves in a microwave oven DO NOT have a wavelength that matches the size of water molecules. Microwave ovens operate in an FCC allowed band from 2.37 to 2.52 GHz.
Broadcasters work with many frequencies above and below that band.
Microwave frequencies do not corner the market on heating. I used to climb broadcast towers for maintenance, and have been exposed to the effects of EMR, from FM and TV antenna bays, and it heats up everything on your body which is made up of metal quite quickly, and can cause burns just by being in the field near the antenna bays. Body tissues that are subjected to very high levels of RF energy may suffer serious heat damage. These effects depend upon the frequency of the energy, the power density of the RF field that strikes the body, and even on factors such as the polarization of the wave. At frequencies near the body's natural resonant frequency, RF energy is absorbed more efficiently, and maximum heating occurs.