Do you want to know how the CSS WG works? Fantasai has written about:csswg, An Inside View of the CSS Working Group at W3C.
touch-actionproperty might be overly-specific to touch interfaces
touch-actionproperty is necessary.
touch-actionis used in an all-declarative use case. (If it is only useful when JS is invoked, maybe its behavior should likewise be handled by JS, not by using a declarative property that’s that expects alternate handling via JS.)