While Democrats nationwide cheer socialist demands to raise taxes , they simultaneously demonstrate every day how incompetently they spend the money they already take from us. Mayor Zohran Mamdani’s fish-eyed smirk in his “tax day” video — smugly gloating, “ We’re taxing the rich !” — was just the most extreme recent example of Dem greed . He insists high-earners “pay their fair share” to fund his dreams of free buses, day care and cheap groceries. Yet on Monday, The Post offered a painful