I think that if you offer Russian criminals millions of dollars for a mysterious device which could possibly cause Havana syndrome, you're certain to get a mysterious device.

This is confirmation bias with the side step of giving a ton of money to Russian criminals.

According to those reports, the US military tested it for more than a year on animals, and found that they suffered similar patterns of brain damage. They didn't just get a device and say "wow, this looks like a bunch of very suspicious electronics, too bad we can't turn it on!"

Naturally the testing claims from insiders could be specious. But once you go down the road of distrusting stories told by spooks, so could the purchase of a weapon in the first place. The CIA might not even be a real thing.

No, I'm sure they tested it, and I'm sure they found "similar patterns".

I'm also quite sure that the kind of person who would say "come on guys, this is just a RF noise machine, if they had used this in Havana we would have known ages ago" would not be trusted to work on such an important and serious investigation.

I'm not positing any more dysfunction than I see on the outside all the time. Gro Harlem Brundtland, former PM of Norway, doctor, and one time head of the WHO, was convinced she had RF-hypersensitivity.

One of my mantras is that powerful people believe all the stupid things regular people believe, they just tend to act differently on their beliefs.

These are not subtle effects. You either have an energy weapon that does visible damage to people and things, or it doesn't. Yes, incompetence is possible. You should not jump to "I mistake a candle for a burning skyscraper" levels of incompetence as your main model for a project that lasts a year and is extremely high-priority.

The rationale for rejecting the syndrome was the reported scientific consensus of the impossibility of such a device being smaller than a large truck. The revelation that such a device is possible, exists, works and is full of Russian parts seemed to change things. Further, the coincidental appearance of Russian agents on video within operational radius of incidents wearing backpacks sized to contain the device raises some questions.

Exactly what kind of device was it that had to be on the scale of a small truck but now can fit in a backpack? What kind of radiation did it emit?