To me any problem that is not a fault with hardware or software but is a problem centered entirely on a human rather than a computer is off topic.
Ergonomics such as "how do I arrange my workplace?" or "how do I stop typing things wrong" are purely wetware problems that are not concerned with problems on the computer itself. They have almost nothing to do with the computer.
A keyboard might have a fault that delays one key over another which means someone types "teh" instead of "the" but it is thousands of some more likely that the human is at fault and needs retraining, perhaps forcibly even. This is probably not a problem with the hardware and is certainly not a software fault. "How can I fix my autocorrect?" would be a valid question, "how can I fix my hands/brain?" would not. The question would have to show adequate research before I gave any credence to it being a hardware fault.
"How do I arrange my workplace to prevent RSI/back injury/groin strain?" is another one I've argued before. We can easily close them as primarily opinion based, because they are, but some people have argued that they are asking about hardware related to computing. Desks, chairs and pencils might be a type of hardware, but they are not computer hardware. This is also another wetware problem.
Ergonomics should not be on topic on SU in my opinion, the problem lies entirely outside of computer hardware and software. As has been stated with Android just because we have a tag does not make it on topic. Questions have to be reasonably scoped and not be entirely opinion based as most ergonomics questions will be. "Well this worked for me but YMMV" would be a very common start to any answer.
To me any problem that is not a fault with hardware or software is off topic. Ergonomics such as "how do I arrange my workplace?" or "how do I stop typing things wrong" are purely wetware problems that are not concerned with problems on the computer itself.