Is the monroe doctrine still in effect today? if so, please tell me why European still have colonies?

There are many locations in the americas and Caribbean that still belong to europeans, however your point of the falkland islands shows the shortcomings of the doctrine, the falkland islands belong to the british, argentina (also a european colony product) invaded the islands to force a claim, after much fighting, and the loss of soldiers, aircraft and naval ships the british reclaimed the island, the monroe doctrine would thereby point out the hypocrisy where you have europeans fighting descendants of europeans for control of an island that prior belonged to neither.