Mostly Apple fanboys, back when that was the Apple kool-aid. Nowadays it's the RISC-V fanboys because... IDK... RISC-V is open-source so that makes it "better" somehow? Or something equally facetious.
Its more than just Apple.
PowerPC, ARM, and the legion of lost 80s/90s processors (SPARC, Alpha, MIPS, PA-RISC) all claimed to be RISC. Furthermore, not a single company claims their ISA to be CISC. CISC is what "other" companies call Intel's design, almost a derogatory term that's pushed upon the competitor to make these other designs feel better about themselves.
If I were to push a company responsible for the RISC-mania, it'd be IBM and its POWER architecture. IBM did many CPU designs and seemed to push RISC as a marketing term the most (even as RISC was used all over the place, IBM was probably the most powerful and widespread mouthpiece to the pseudo-concept).
That being said: deep discussions about pipelines, processor efficiency, throughput etc. etc. allowed for these companies to leapfrog and advance CPUs. Alas, the "CISC" x86 instruction set by Intel (and later AMD) turned out to also take all those innovations anyway, and become the fastest processor of the 2000s, 2010s.
-----------
RISC-V continues the tradition of claiming advanced ISA design, much like its SPARC / ALPHA / MIPS bretherin before it. After all,
every new CPU design needs to say why its better than the "CISC" machine over there, without necessarily using the trademarked term (Intel) in their marketing.
-------
I think with all the processor / ISA wars of the last decades, I've come to the conclusion that it doesn't matter. AMD came out with the dual ARM+x86 "Zen" design back in 2016, proving that all of these ISAs can convert between each other on a modern core anyway. And that's when I began to realize how similar ARM vs x86 was at the instruction level.
ARM stands for "Advanced RISC Machine" by the way, and was one of the other major marketers of the RISC term. (ARM wasn't very big in the 90s, but is a big deal now). With AMD making ARM + x86 compatible processor (even if it was just for its own internal tests), it proves how bullshit this whole discussion was. Decoders are not the critical element of modern processors, and they can be swapped out without much hassle. (At least, not a hassle for these multi-$$Billion megacorps).
