Extremism has gone mainstream. That warning comes from the Southern Poverty Law Center with the release of its “Year in Hate & Extremism.” The annual report contends that a loose coalition of “hard right” groups including militias, anti-government extremists, conspiracy theorists and white nationalists are working together to undermine democracy. The SPLC’s report, released Wednesday, counted 1,221 hate and anti-government extremist groups active in 2021 in the United States, including 34 in Georgia. Those numbers represent a third straight annual decrease, but the progressive non-profit based…