@jmc
Physicists often have trouble rationalising the effects of artificial EMFs on biological systems and whilst your views are commonplace I fear they are mistaken.
When you say that we are "bathed" in microwave energy, this is misleading.
We are exposed only to IRO 0.000,000,000,000,010 micro watts per square meter of microwave energy from natural sources. Cell phones, on the other hand, are permitted to expose your brain to 9,000,000.000,000,000,000,000 microwatts per square meter.
This is a difference of around one quantillion fold or 10 to the 18. (My maths might be out by a little but it is there or there about). You cannot say we are "bathed" in radiation from the cosmos any more than you can say you are bathed by Scottish spring water in the Sahara!
The story linked above is by Dr Andrew Goldsworthy - a biologist at UCL in London. His work, and others like him (Prof Martin Pall, etc) show that low level information carrying microwave signals interfere with voltage gated calcium ion channel signalling - this seems to be an emerging understanding of how leakage of the gut brain barrier is caused.
It's not about whether the signals have the energy to cause ionisation - it's clear that, directly, they don't. But they do have the means to interrupt and interfere with intra-cellular signalling, leading to a flood of calcium into cells, in turn leading to ROS production, in turn leading to cell damage, protein, lipid, DNA damage, etc.
I hope people will look into this more for themselves and limit their exposures. As our physicist friend knows, distance is your friend with microwave energy - exposure falls off dramatically with distance from the emitting source.
Respectfully,
ocm