There's nothing racist about the Gadsden flag. It's unfortunately been used a lot lately by some d-bag far-right "freedom lovers". It was created during the American Revolution. The snake represents the 13 colonies joined in union together that will strike if stepped on (like a rattlesnake), that comes from the "Join or Die" cartoon attributed to Ben Franklin in 1754 where each part of the cut up snake represents one of the 13 colonies: