Transit source seems fine I think you're just misinterpreting it. That first source says about a third board without paying, not 90%. The 90% number you're quoting is I assume from the <10% farebox recovery which is a different metric from fare evasion. North America generally has low farebox recovery (car centric development therefore transit needs bigger subsidies to compete) and the pandemic made it worse. Don't get me wrong the numbers aren't good but I don't think it's evidence that Seattle is an especially low trust society like you're implying, I think it just indicates a lack of enforcement - a third is in line with fare evasion problems in other places in the world when they lack enforcement. People in Seattle behave no different from people in other places - they estimate risk vs reward in a free ride and some fraction of people lack a moral compass or are so poor that the benefit is significant. There's a reasonable line of thinking that 0 fares are best for society as a whole and I've heard this promoted among PNW urbanites so it wouldn't surprise me if enforcement is intentionally low to make it a sort of sliding scale farebox recovery, in which case a high fare evasion is not evidence of low trust, just of a highly progressive political culture, and something opposing propaganda will not hesitate to harp on.
Theft rings are pretty common in bad neighborhoods throughout north american cities. The existence of a policy to help grocery stores in high crime areas doesn't support your thesis since it's going to be used on a vast minority of stores, not indicative of "rampant" (most stores in Seattle seem fine in my experience), and not indicative of a broader trend in trust.
And here is some data counter to your thesis https://www.pewresearch.org/2025/05/08/americans-trust-in-on...
It seems to me that Seattle is an especially high trust society by US standards (largely due to high income I suspect), and the things you're pointing at are evidence of the opposite of your thesis - more likely to be symptoms of high trust than low trust.