Ah... my physics course was very short, and tried to cover a bit of everything, because I did Computer Science. So I really don't know the details. I just assumed it would apply to any polar molecule to some degree and looked up random ones for that joke.

I do know that Microwaves use a frequency around 2.4 GHz - 2.5 GHz, they can disturb Wifi if they leak. But I assume that is just because the unlicensed ISM band is there, and hasn't got anything to do with water specifically.