I don't know what math rock is, but King Crimson definitely doesn't get the credit they deserve.
Discussion
There's good math rock out there, like Battles, Don Caballero and Hella, but there's also a bunch that copies the intricate guitar sound from the clip above. I mean, they're ripping off great source material but, as you said, Crimson deserve even more credit than they get.
Thanks for the recommendations. I'll check them out