JS devs don't believe colleague who claims browsers have native scrolling

An experienced web developer, who joined a large tech company in Nottingham last month, claims to have discovered a hidden, secret feature built into all web browsers: page scrolling. According to him, if one simply does not implement scrolling with JavaScript, then any page is still going to be scrollable by default. Moreover, this "native scrolling" (sic) is fluid and smooth: properties often unavailable to JS-based solutions.

Unfortunately, nobody in the team shares his enthusiasm. Even after demonstrations, web developers of all levels do not believe this feature exists and insist on implementing scrolling themselves. Many have the opinion that their colleague has fallen victim to a conspiracy theory.