Did you notice that he used the dictionary definition (complete with screenshot)?

If you're going to argue with a dictionary, it would be more convincing if you did more than just say, "No, you're wrong. I like this definition better."

Dictionaries can be wrong. But you need to explain why (e.g. by referring to a more authoritative source, using Google ngram if applicable, etc.).

(Edit: Marnita does provide a powerful defense of her perspective a few comments in — I encourage any reader to keep digging into the back-and-forth below until you get to it!)

Note: using a racial slur against someone is "antagonism" so meets the definition used. So your concluding point is already refuted by the original post, no extra work needed.