が-marked object with stative predicate

Stative adjectives of ability and preference (好き, 嫌い, 上手, 下手, 得意, 苦手, 分かる, できる) take their 'object' with が rather than を — because they describe a state, not an action. The full frame is X[topic-は] Y[subject-が] STATIVE-ADJ.