Joel Skousen (personal communication, 8 December 2002) suggests that the word righteous may be intrusive here in 3 Nephi 7:7. The text intends to say that “the more part of the people” had become wicked. Both 1830 and 𝓟 agree, so 𝓞 undoubtedly read “the more righteous part of the people”. If the word righteous is intrusive here, it must have been inserted in the text during its dictation.
The larger passage here suggests that righteous was probably in the original text. Mormon himself wrote the equivalent of “the more righteous part of the people”; but he immediately realized there was a problem with referring to the righteous part of the people, so he explained that most of them had become wicked—only a few righteous were left. Note further that the following verse explains it all correctly:
In other words, Mormon apparently intended to write the equivalent of “the more part of the people” in verse 7 (not just in verse 8), but he accidentally referred to the righteousness of the people too early, which forced him to cut off his original clause and write a corrective although-clause (see the discussion under the next variant).
Summary: Maintain in 3 Nephi 7:7 the incorrect use of righteous in the phrase “the more righteous part of the people”; Mormon’s subsequent corrective reading suggests that he did not want to refer to righteousness here, but having done so, he was forced to contradict what he had just written by adding an although- clause.