While many questions on hardware multithreading on SuperUser will concern Intel's Hyper-Threading, a significant fraction concern hardware multithreading more generally. (Those concerning actual Hyper-Threading could generally merely add the Intel tag to clarify the specificity, though some Intel products use multithreading but are not marketed as Hyper-Threading, e.g., Xeon Phi.)
In some cases, the poster of the question is not aware that Hyper-Threading is Intel-specific (and a marketing rather than technical term), so making hyper-threading a synonym for hardware-multithreading would make distinguishing Intel-specific (or more specifically Hyper-Threading specific) questions from more general hardware multithreading questions difficult (unless a more informed person added the Intel tag) but would allow generic hardware multithreading questions to be more accurately tagged.