This is an Australian affect. We call microwave ovens microwaves.

Not really:

Consumer ovens work around a nominal 2.45 gigahertz (GHz)—a wavelength of 12.2 centimetres (4.80 in) in the 2.4 GHz to 2.5 GHz ISM band

"Microwaves" as in "the part of the electromagnetic spectrum we call microwaves".

And as they correctly point out, that consumer ovens use a specific frequency has nothing to do with it being a resonance frequency of water, but it being a reasonable to use and legal frequency to do so. They would work on 1 GHz or 5 GHz too.

>"Microwaves" as in "the part of the electromagnetic spectrum we call microwaves".

The parent wasn't speaking about "the part of the electromagnetic spectrum we call microwaves" in general, but about what's "used in microwaves to heat our food", i.e. microwave ovens.

I'm fairly sure they were speaking about the meaning of the word were their assertion is correct and makes sense. The urban legend part is "2.4 GHz is choosen because it's a resonance frequency" after all, not "2.4 GHz is what's used in microwave ovens".

Yes I meant EM waves here, not microwaves which can be taken to mean the devices.

Check my submission history for my creds in this regard.