It's interesting that you remember "an extra baggage search" and "an hour going through an invasive species screening." I'm guessing you've only visited Australia once, quite a while ago. I've flown in and out of Australia 2-3 times a year since 1990. I don't know what you mean by "extra baggage search" apart from a standard customs inspection. There was a short period several years ago when visitors had to have their shoes disinfected to keep BSE or some other livestock disease out.

I'm not saying these things didn't happen to you - I'm sure they did. But they're not a common occurrence. Even so, you remember these "extra" inspections and it colours your impression of Australia.

Is it surprising, then, that foreign visitors to the US might remember being barked at, scolded, and being exposed to a confusing set of arbitrary rules, and that this might affect their impression of the US? These things are, IME, far more likely to occur at a US airport than "an hour of invasive species screening" at an Australian airport. Is it surprising that some might be so irritated by it that they decide to take their tourist/business dollars elsewhere?

This is a really significant point. The US and UK invented the liquid and shoe lunacy (and the UK spread it to the rest of the EU). Int'l airlines had to comply if they wanted to fly to those markets. TSA tells everyone that there is international consensus on the danger of liquids and shoes, which is a lie, as the domestic procedures show.