Here's my lived experience: algebra in 7th grade, black boy. I'd have been better off taking it later, and making it up with summer geometry, trig, and precalc courses /certs in between algebra, algebra ii, calc, and diff eq/calc ii in high school. If that meant my classmates could have a better chance of keeping up, all the better; being in the historically lily-white gifted track at my magnet high school didn't do much in the way of convincing my teachers not to give up on me at the first sign of weakness. Yet another nuance you either miss or refuse to acknowledge.
The supplementary courses were provided by the school system, by the way. I would have taken them, but I was working or otherwise predisposed. If you really cared, you'd be advocating for the same (especially since a large portion of the general failure to attain math competency in America is due to our excessively long summer breaks).
Your "dogwhistle" is itself a dogwhistle (your obvious implication being "only a racist Trumptard could support allowing students to take algebra in 8th grade"). Ironic, in that the people defending the decision implicitly believe that non-white people are less capable of learning algebra than white people. Which itself is stupid, from a historical point of view. Who, after all, first formulated algebra?