Also, any Government that refuses to "play ball" when it comes to infectious diseases should be ostracized - even put a mandatory two week quarantine on everyone returning from countries who refuse to work with the world to prevent the spread of these diseases.
As long as nations are so codependent on each other, the ability to police what they do within their own jurisdiction is going to be extremely limited, especially for nations with a lot of political and economic clout.
While there should certainly be standards, with incentives to adhere to them, and consequences for not, I don't think arbitrarily punishing one's own travelers would accomplish much of anything.
We have to come to terms that we cannot expect every regime to be willing or able to do what is in the world's best interest.
Personally, I think those entities that can should treat these problems as an intelligence/counterintelligence issue, and have people on the ground collecting data on potential health threats, with or without the consent of the governing state.
A large percentage of the elderly who have passed away in my state (Massachusetts) did indeed live in elderly homes (similar to Washington State.)
This is true, but there are still countless non-healthcare staff and visitors that are potential transmission vectors in such settings.
A big part of the myriad of problems with assisted living facilities stems from just how few healthcare workers there are. The COVID-19 deaths in these places is shining some light on how shoddy they often are, but unfortunately, the response seems to be to give them immunity, rather than hold them accountable, at least in much of the US.
And I'll disagree with you that at the beginning of the COVID-19 outbreak we knew how bad it was. In January the World Health Organization (WHO) was still saying there was "no clear evidence" that the coronavirus could spread between people.
COVID-19 Timeline:
https://www.nytimes.com/article/coronavirus-timeline.html
Absence of evidence is not evidence of absence.
The assumption, even back in early January, was that SARS-CoV-2 could spread between people and that there were likely asymptomatic carriers. Fauci stated this again in very early February, even after some issues were discovered with the first reports of asymptomatic carriers outside China.
To think that people with no symptoms couldn't transmit this pathogen was far fetched to the point that the safest assumption was always that it could. If we had waited for conclusive evidence that SARS-CoV-2 could indeed to the same things that we've known for decades that it's closest relatives were able to do, it would have been too late...well, here we are.
In the absence of proof, you extrapolate from what you know. The world has had considerable experience with other coronaviruses, but collectively chose to ignore the lessons previous outbreaks and research taught.