Sorry. Your race card is over drawn. You have jumped the shark and nobody care when you cry "wolf!" anymore.
You should have saved that ammunition for an actual threat.
It's a well they have gone into too many times and now it's dry. Crying racism used to work for the left as it was their go to response when losing a debate against a conservative. The idea was to get you off of the subject they were losing and get you to defend yourself. But, as you said, they've overdone it and now most people ignore, and many times, laugh off the accusation.
The problem for the left is they never learned to debate beyond the name calling so that's all they have left. They never developed any debating skills to debate their positions in an intellectual manner
