I agree it's a fix for the animation double click jiggle, but why didn't they address in 10.3.3? Why wait for 11 and a new phone?
I've been on your side from the beginning of this saga
What if Apple just wanted to go back and fix the so-fast-that-it's-messing-up-the-double-click-multi-task-animation home button on the 7's? I tried a 7+ on ios 11, and the slower response reminds me of a experience where the system doesn't do anything until I "release" the home button instead of responding when the home button is "down".
I'm kind of leaning towards Apple just wanted to "fix" this behavior of the "down" position response because that isn't how the physical home buttons function.
I dunno..... But, yeah, I also subscribe to the idea that Apple doesn't give a flip about last years' phones and optimizing for them....