Markets fail because people fail. However, markets also embody a drive toward continuous self-improvement: their "failures" are the means through which they become ever more successful, ever more capable of multiplying scarce goods and services of ever higher quality. On the other hand, politics not just fails, but it is a failure, a permanent and inherent one at that: the more it "succeeds" in accomplishing its goals, the more miserably it fails in making the world better, the more it plunges the world into the planned chaos of instutionalized violence, aggression, coercion, and parasitism.
In other words, embrace market "failures" as valuable lessons in the school of prudential virtues, but denounce and work against political "successes" by recognizing them as inevitable social tragedies waiting to happen. Side with the best, but not with the best for the worst.