Also, banning for dogwhistling is ridiculous, especially as it appears to be based off that one post.
Dog whistling is an excuse to impugn the motives of your political opponents and it's generally used wrt hidden racist meaning to common phrases used in politics. It's generally considered to have started in the Nixon era, specifically with his use of the term "Law and Order" with hte evidence fo such being that he was using that term to target Puerto Rican and Black radical groups. To quote Nixon after watching one of his own commercials: ‘Yep, this hits it right on the nose ... it’s all about law and order and the damn Negro-Puerto Rican groups out there.’”
That seems daming on its face, though in the late 1960s and early 1970s we had several actual domestic terrorist organizations running around the United States, a Puerto Rican independence movement was known for bombing buildings in New York, while groups like the Black Liberation Army were openly hunting down Police. This was the era of Assata Shakur, Eldrich Cleaver, and Bill Ayers. If we think Antifa is bad today it was nothing compared to what a few small cells across the country did in that era.
Today it's usually used in reference to terms like "rioters", "inner city", or "Sharia Law". Each of those, among others is considered a coded racist insult. That means that these topics can no longer be discussed. If you mention Sharia Law in a critical way, well that just makes you a hidden racist communicating in code to other hidden racists. If you say the inner city has problems then you just hate black people. Or, wrt "ethics in game journalism" means you are a secret sexist who doesn't weant those cootie filled girls playing your games. Saying you favor "equality" is a dog whistle that you are a secret sexist too.