Maybe it’s because the rest of this fair state doesn’t always have its largest city’s interests at heart. But almost any time the Legislature proposes a law exclusively affecting Los Angeles, it’s a rotten deal.Two years ago, for instance, Sacramento proposed to ease the law on the breakup of cities — but only in Los Angeles. Once the legislation was rewired to let any California city split, lawmakers lost interest. If it doesn’t just stick it to LaLaLand, why bother?Now a similarly focused law crawls through the Assembly. AB 83 applies only to Los Angeles County, and in theory, I should want it, since it purports to benefit those who write at home. But the Legislature’s analysts were critical of it. So am I.