Rather this is a typical HN religous-substituting faith in "progress" (of the non-reflective "just more of everything" variety), and a knew-jerk reaction to any mention of limits to growth and other concerns aside from enlargement.
I think the stance comes from one's position towards the "want for more" attitude in humans.
If you think the thirst for material wealth and welfare can be somehow limited or contained at scale, you will find the concept of de-growth very appealing, because it solves a bunch of big problems we have.
If you don't think such thirst can be limited, which is arguably what modern history might suggest, then the concept is clearly impossible to realize and not worth discussing.
Every. Single. Time.