I have been using the Aya Neo and OneXPlayer a ton throughout the last few months and this issue still is persistent in the latest beta of Steam. I'm really hoping this gets addressed sometime in the future and it isn't deemed non-issue because of the GamepadUI/Big Picture Mode options being available.
The modern Steam desktop client and BPM seems to respond to touch scrolling as you would expect
Closing per the last comment.
Nothing extracted yet.
Steam isn't optimized to make use of touch features that just works on Windows such as scrolling through your game Library.