German Chancellor Bismarck once noted, "There is a special providence that watches over fools, drunkards, and the United States of America."
https://piefed.social/c/historymemes/p/1834739/german-chancellor-bismarck-once-noted-there-is-a-special-providence-that-watches-over-f
IIRC Russia was super weakened by a war, and didn’t have the soldiers to protect Alaska, so anyone could have decided to take it, and Russia wouldn’t have been able to fight back. So why not make a quick buck off it instead of having it embarrassingly taken from you?
International community would object and stop take illegal takeover.