So the Hundred Years War is BS, as is the 30 Years War, the War of the Austrian Succession, etc etc?This claim is BS especially since the Ottomans used divide and conquer on Eastern Europe why Britain, France, and Spain could never successfully imitate the policy of the Ottomans. Also backwards people have a a tradition of using divide and conquer such as Mongols disrupting relations between various Chinese states, Ottomans turning Muslim nations against each others, and Japan using divide and conquer when they tried to conquer Korea by siding with one Korean aristocrat.
Not to mention the American Revolution, Britain tried to use this but it failed.
Just because familiarity meant divide & conquer tactics BECAME less successful in Europe it does not mean it didn't happen!
I also think you need to explain what you mean by "backwards people" as use of it sounds like you subscribe to some kind of racial theory as to why Europeans succeeded first rather than luck of geography and timing.