No, it's been around since the '70s at least and is an offshoot of so-called "Critical Theory," a product of the Frankfurt School of scholars. Much like most of these products, it is usually a degenerate form of some previously existing philosophy, as Michel Foucault was at least in part a degenerate Nietzschean.
Nick Rekieta covered it a few times. The term we heard during GamerGate, and were told under no uncertain circumstances were we allowed to talk about because it was antisemetic to notice things, was Critical Marxism.
Critical Marxism is blatantly Marxism retooled away from Economic majority vs minority into Cultural majority vs minority -- i.e., blacks vs whites, gays vs straights, troons vs sane people, etc. It's blatantly an attempt to find some new wedge issue to try and tear apart Capitalist societies to try and get their little communist revolutions in. I haven't dug too deep into it -- again, it's one of those "notice things" that you aren't allowed to talk about if you're from the outside looking in -- but it wouldn't surprise me at all to find that Critical Marxism is just shorthand for "Critical Marxist Theory."
Contrast Post-Moderism, which was retooled to be Marxism as a religion, with a focus on power as a means to an end. "I know the facts and logic say that Marxism doesn't work, but I FEEL it should, and don't my FEELINGS count as much as your facts? They do if I have enough power to stop you from speaking!" Combine the two and you get Identity Politics, aka Wokeism, aka SJWs.
The way Nick mentioned it, I guess Critical Theory is when you take a presumption and look at a work in a new light based on that new presumption, and see how it unlocks new information and sheds new light on existing information. It's a valid, but extremely high level scholarly technique, and can't be actually taught to kids -- even in colleges, it's a in depth class usually taught by someone with a Ph.D. to... postgrads? I.e., there's no way your glorified woke babysitters in elementary school can teach it. And they know it, but they're using it as a cudgel.
The thing is, the presumption that you have to take with Critical Race Theory is actually what Critical Race Theory nutters are trying to push on everyone. And that presumption is your bog standard Neo-Marxist "All Whites are Racist, All Blacks are eternal victims, Whites deserve nothing and stole what they have, while Blacks deserve everything and have had everything stolen from them" narrative. They're trying to push Woke Racism under the guise of the Leftist version of Intelligent Design.
"Lets presume that all white people are racist monsters who are responsible for all the suffering in the world." Um, ok. Why do pre-teens need to presume this? When are you giving them any alternate viewpoints? Since when do Public Schools teach any form of BELIEF SYSTEM? When are we going to presume that they're actually not, in fact they may be the only thing keeping civilization together in most of the Northern Hemisphere? Never? That would be racist? Right then.
Also, I lament the fact that no one is examining Critical Dindu Theory, the examination of American history under the guise that maybe Blacks really are inherently less intelligent than the rest of humanity and what that meant for the past 500 years of race relations, for example. Because doing so would be stupid as fuck, and almost as racist as your average anti-racist white progressive or black siniqua chimping out on twitter.
