Grammatically, we expect the object form of the pronoun after prepositions; thus Joseph Smith edited the text for the 1837 edition from “unto they” to “unto them”. The critical text will restore the ungrammatical pronoun usage unless there is specific evidence that a scribal error is involved. For another example (involving I versus me after against), see 1 Nephi 7:6. For a complete listing of this type of editing, see under pronouns in volume 3.
Summary: In the critical text we follow the original pronoun forms (as found in the earliest textual sources), even when these forms are ungrammatical in standard English; here in 1 Nephi 17:44, we restore the subject pronoun they after the preposition unto (“and ye are like unto they”).