We're contending with the reasoning behind an observation, but the observation is already useable to the author of the post — if true. Is the author of the post seeing improvements in candidate quality because Deno is actually a proxy for burning the midnight oil? Who knows. If we generalize to Java vs Go will the observation hold? Who knows.

But as chrisco255 pointed out, neither usage of Deno nor applying a weight to some observation will reduce your hiring pool.

I would also say that a technological perspective of "right tool for the right job" is somewhat independent to the expensiveness of your hiring pipeline. Sometimes Erlang is the right tool for the right job, but that undoubtedly changes the experience of hiring.