I am 99% sure that's not the same benchmark. The cheapest way to break 12,000 CPUMarks is a $370 Intel Core i7-5820K (15MB of cache, 6 cores, 12 threads).
Perhaps they are using the Android benchmark. A score of 12,000 is about what a quad core ARMv7 phone gets.
Compared with the cross-platform Geekbench3 a HTC One (ARMv7 4 core, 1.7-2.2Ghz, 12,000 Android CPUMarks) gets between 2,000 and 3,000 points[1], while a 5820K gets around 20,000 points[2].
Ah that would explain it. That's a pretty misleading claim then. So I guess ARMs are still pretty slow and Amazon is not all that terrible after all performance-wise. That also makes more sense intuition-wise.
Just to give another data point closer to price an Atom N2800 (which kimsufi offers with ssd for the same monthly price) gets around 1100, so competitive but not world changingly so.