𝓞 is extant here and reads “the sins of men”, so in this instance there is no question about the original reading. When copying from 𝓞 into 𝓟, Oliver initially miswrote men as the world. Sometime later, perhaps when proofing 𝓟 against 𝓞, he crossed out the world and supralinearly inserted men (the level of ink flow is somewhat heavier). The phrase “the sins of men” is unique to the text here, although there is one instance of the related “the sins of every man” (Alma 5:48). But “the sins of the world” is very common in the Book of Mormon text, with 17 occurrences. Oliver was obviously influenced by the frequency of “the sins of the world” as he copied the text here from 𝓞 into 𝓟.
Summary: Follow in Alma 30:17 the reading of 𝓞, “the sins of men”, instead of the much more common “the sins of the world”, the initial reading in 𝓟.