After years of playing the nice guy, Airbnb now finds itself on the defensive in some of its biggest markets, and the pressure doesn’t suit. The company has unleashed lawsuits, held rallies, and spent millions on lobbying campaigns. It has decried political adversaries and brandished opposition research on hotels. The clashes lay bare an ugly truth: Under fire, Airbnb is a corporation like any other. It’s not that nice at all.