For reference, the parent asked what studies support the grandparent's claim. I believe the comment has been deleted by HN algorithm and frankly it makes no sense to me - at least in this case.

The parent comment has been downvoted/flagged to death by users, at which point HN will no longer show it.

So no "HN algorithm", just users flagging.

You can set the "showdead" flag in your profile and you will see dead posts, including this one (grayed).