Personally speaking,this sentence is a little bit rude.

The countries defeated easily are all small ones around, which get very close to the edge of the modern civilization. 吊打= defeated easily

well,there is not a subject for this sentence. so its potential means perhaps is ' it ' doesn't  dare  to fight with the really big power but bullys  surrounding small ones. 吊打 means doing something as easily as fighting with a man who is being bound in the air.

落后就要挨打