Duden, the famous German dictionary, defines kontrovers: entgegengesetzt (opposite, contrary), strittig (contestable, debatable), umstritten (contended, contentious). Synonyms are: gegensätzlich (opposed, antithetic), in sich uneins (in disagreement), widersprüchlich (contradictory), zwiespältig (conflicting, ambivalent), anfechtbar (challengable), angreifbar (attackable, vulnerable), kritisierbar (open to criticism), disputabel (disputable). From the Latin controversus: facing or standing against; contra: against and versus.
Entgegen. Gegen. Wider. All meaning against. Germans like clarity. Not black and white, but take a position. This or that. In many ways the German people defines itself by comparing itself over and against other peoples, in how they think, act, work, live.