Maybe the Government in Guam don’t want “foreigners” to bring the sickness with them
Or occupy what little capacity they have for isolation of Covid-19 affected persons on the island.
Maybe Hawaii or California could accommodate US service personnel in need??
They are not “worthless foreigner” after all
They may have to endure a trans-Pacific crossing, (Similar to what have been suggested for the crew and passengers on the two cruise ships heading for Florida)