Living on an island in the path of where typhoons are prone to go probably isn’t the wisest choice of where to retire, having Tricare or not. So much is destroyed, those retirees are lucky to be alive. Maybe they need to come back to the states for their medical care until that place is reconstructed and services are restored - however, it appears that could take years.
Then I guess you would say that living in Oklahoma is not smart either. Or maybe California because of earthquakes.
Typhoons are part of life in the Philippines, just as tornado and earthquakes are a fact of life in tornado alley and the west coast.
Also, many retirees can’t return to the US because they live on a small pension or have Filipina wifes and extended family in the Philippines. It is very difficult to get a visa for a Filipina from the US Embassy and immigration laws requires the sponsor to have an income high enough to guarantee that the spouse will not end up on public assistance.