By that logic, using more than one thread at all for Dolphin is a speedhack. The devs are fine with dual core being the default option, as, when properly synchronised, it can produce 100% accurate emulation. This same idea technically applies to LLE on thread, just proper synchronisation with the Zelda microcode would stall everything so often it would be potentially problematic.
OS: Windows 10 64 bit Professional
CPU: AMD Ryzen 5900X
RAM: 16GB
GPU: Radeon Vega 56
CPU: AMD Ryzen 5900X
RAM: 16GB
GPU: Radeon Vega 56
