Repeatedly calling Black leaders "low IQ," isn't expressing a political disagreement. It's a racist dog whistle.

[bigtree]

28. it's a political dog whistle

...it just is; no matter how well understood it is to you; how inept; or how obvious or overt you feel it is.

A political dog whistle can be overt. In fact, there are instances where dog whistles are used in a way that is more explicit than subtle. For example, during the Civil Rights Movement, politicians like George Wallace and Richard Nixon used coded language to appeal to white voters who were resistant to racial integration and social change. Terms like "law and order" were used to subtly convey anti-black sentiments without being overtly racist. This strategy allowed them to mobilize their base without alienating moderate voters.

In 1981, former Republican Party strategist Lee Atwater, when giving an anonymous interview discussing former president Richard Nixon's Southern strategy, speculated that terms like "states' rights" were used for dog-whistling. Atwater was contrasting this with then-President Ronald Reagan's campaign, which he felt "was devoid of any kind of racism, any kind of reference". However, Ian Haney López, an American law professor and author of the 2014 book Dog Whistle Politics, described Reagan as "blowing a dog whistle" when the candidate told stories about "Cadillac-driving 'welfare queens' and 'strapping young bucks' buying T-bone steaks with food stamps" while he was campaigning for the presidency.
https://en.wikipedia.org/wiki/Dog_whistle_(politics)