CRT (as a comprehensive philosophical study) is a college-level course.
However, outgrowth concepts of it have been incorporated into public school curriculums in certain places
It'd be kind of like
"Comprehensive Cardiology is a graduate level study that's taught in Medical School, they're not giving cardiology courses in 4th grade"
...and...
"Kids are taught that mammals have hearts with four chambers that pump blood in public school" (which is an outgrowth or "watered down" sub-set of cardiology)
The first statement being true doesn't mean that the latter is false.
In the case of CRT, while it's true that 4th graders aren't reading the complete in-depth writings of Derrick Bell and studying them at length...there are some public schools in some of the more progressive states that have incorporated portions of "The 1619 Project" and NYC and Seattle Schools have incorporated some of this into the curriculums
BLM at School is committed to teaching truthful histories and amassing the powerful practices, creative tools, and key strategies by which past, present, and future generations can advance the...
www.blacklivesmatteratschool.com
...which incorporates ad-hoc subsets of CRT.
Or perhaps, a better analogy that may highlight what I'm talking about.
If a school was teaching that there was a man named Noah who gathered 2 of every animal, and loaded them on a boat to ride out a global flood, and teaching it as historical fact....
Most people would rightfully say "Hey wait a minute, you're teaching religion in schools, I don't agree with that"
If someone gave the defense of "nope, Religion and Theology are seminary-level graduate courses, we're just talking about a guy with a boat and some animals during a big storm... you guys are just overreacting"
Nobody would accept that as a genuine/legitimate defense...