That isn't quite the conclusion the article draws though. Most people would interpret "positive/negative" impact as meaning whether the badge will help or hurt

That isn't quite the conclusion the article draws though. Most people would interpret "positive/negative" impact as meaning whether the badge will help or hurt you in your job search. Instead, the article evaluates whether engineers with the badge are higher or lower skilled than average. As such, the only conclusion you could really draw is if you're a hiring manager, you should not view an "Open to Work" badge as a negative signal for a candidate.