Oh, Dan. If you do a tweet that is basically available to the entire planet that is dependent on someone knowing about a particular feature on your shows throughout the years that probably only a few people will recognise, then what do you think is going to happen?
Idiotic? Ill-thought? Clumsy? Yes, and now you've got to live with the consequences. After avidly following you for 25 years, and not once hearing or seeing anything the slightest bit racist, I don't think you did that with any malicious intent. But that said, I can't defend you on this. You should have thought of the possible ramifications, and not go near social media after you've had a few drinks.