I found your question/answer ( How fast does application response time need to be? ) quite interesting. It's factual, helpful, and just plain interesting, so to me that's on topic. I'll go upvote in a moment.
I'd say that ( http://superuser.com/questions/840632/why-do-i-sometimes-type-the-as-teh-mean-that-the-response-of-keyboard-is-too ) , while not greatly phrased, is on-topic, because the user is asking if a hardware issue is causing the typos. I don't agree with why it was closed. However I think it was rightfully closed, because in addition to poor phrasing it wasn't generating good answers. No different than closing an acceptable question that ends up generating nothing but opinion-based answers.
Based on the 2 examples given I really don't see the alleged gray-area (not saying it isn't there), but setting that
aside, I agree with you that You can't talk about the hardware or user interface and exclude half of the equation.
I'd say if it is a question that a reasonable google search can't solve, and it can be factually answered with answers
that are worth their weight-in-bytes, it's on topic.