Because the Epistle of James is part of the antilegomena. Eusebius actually says the same:
"Among the disputed writings, which are nevertheless recognized by many, are extant the so-called epistle of James and that of Jude, also the second epistle of Peter, and those that are called second and third of John, whether they belong to the evangelist or to another person of the same name." - Eusebius, Church History, Book III, 25:3
The Antilegomena includes Hebrews, James, Jude, 2 Peter, 2 & 3 John, and the Apocalypse of John. As well as certain books which aren't recognized in the Canon today: 1 Clement, the Shepherd, Epistle of Barnabas, and the Didache. Eusebius calls these rejected (Book III, 25:4) but they are mentioned as Antilegomena in the the writings of the other fathers, and the Muratorian Fragment, and are also included in Codex Sinaiticus.
-CryptoLutheran