Chicago Alderman James Gardiner violated the First Amendment when he deleted critical comments from his official Facebook page and sometimes blocked the critics themselves, a federal judge held Monday.In a written opinion, U.S. District Judge Sharon Johnson Coleman of the Northern District of Illinois ruled Gardiner had imposed impermissible restrictions on comments on his page based on their content or writer.Coleman acknowledged Gardiner has unblocked six constituents who filed a proposed class-action lawsuit against him …