Honestly wonder how much of a HN crowd viewpoint that is. I'm not sure there's too much "correlation" between the two. Instead I'd say that if your job involves communication and data, then that necessitates decent visualisations and whatever "design skills" that entails.
Honestly, you don't need "design skills" to make a decent graph ... just the wherewithal to think about what would make a graph clearer/easier to understand the same we expect of ourselves with writing.
Ok ... then aren't we stretching the term "design skill" too thinly then, to the point of disrespecting the actual skillset?
I suspect there'd be a tendency to presume a design process is more like solving a problem with a clear techniques for arriving at an objectively correct solution, when in reality, it can and often if just the iterative process of assessing-adjusting-repeat. Being better at these things to the point of sometimes reducing the iterative loop to 0 repeats is "design skill". But the essential base-line ingredient, IMO, is being willing to enter the iterative cycle at least to some extent.
Honestly, you don't need "design skills" to make a decent graph ... just the wherewithal to think about what would make a graph clearer/easier to understand the same we expect of ourselves with writing.