It's not hard to spot a bad idea. It's usually presented by someone who can easily play the victim card - and almost instantaneously does when criticized.
When Obama presented socialism to America, immediately he suggested that such criticism was born out of the fact that he didn't "look like other presidents" (his words). Never mind that socialism always fails.
Good ideas area exactly that - good ideas. The ideas aren't attacked, but instead their proponents are attacked - as racists, as fill-in-the-blank-ophobes, as privileged, and so on. You recognize an inarguable idea when the people pushing the idea are insulted and not the idea itself.