Not surprising at all. The city council chose to screw Kagan out of his current district lines. Why compete in two difficult races (competitive Democratic primary against fellow Councilmember Justin Brannan and a competitive general election against a nameless Republican in a right-leaning district) when he could skip a step and challenge Brannan directly in just a single race? The precedent was set when this strategy worked for Alec Brook-Krasny last month.