Sometimes, reading the #Phoronix forums is just absurdly funny.
First, the most glaringly obvious thing is that KVM and QEMU are two separate projects and QEMU can, optionally, use KVM under Linux for hardware-acceleration. If it doesn't it will virtualize in software and not use KVM. So, not only is the first comment true, the second completely misses the point.
Additionally, it's a quite wrong too. Yes, VirtualBox' software-virtualization stack was based on QEMU, notably the device emulation part (still existent in VBox) and the static recompilation to enable guests to run in ring-1/3 instead of ring-0 (removed in VBox 6). To call VBox a *fork* of QEMU is quite strong. And, as explained earlier, completely irrelevant to the discussion anyway.
Phoronix (and #HackerNews tbqh) is really the #Heise forum of the English speaking world :'D