what does "for less than he had done"mean?
There was little doubt about the political convictions of the sniper. It was assumed that he and his accomplices, whose existence was also assumed, were agents of the Radical Right. This was true even of the surmises of members of the John Birch Society, and next morning thousands of communities would be retelling the story of the local rightist who had been indiscreet enough to express his elation in public. Elation was unwise, anywhere. America was in no mood to tolerate its haters. Men were assaulted, or at the very least insulted, for less than he had done—driving home from the Trade Mart, Treasurer Warren Harding noticed a riflemen's association sticker on the windshield of the automobile behind him; swerving around, Harding blocked the street and placed the driver under citizen's arrest.