(2) The Protestant Church of Christ objects to a concept of original sin.

The Protestant Church of Christ uses Ezekiel 18:20 as a proof-text, which reads: The son shall not suffer for the iniquity of the father. Ezekiel was not arguing against the idea of original sin; he was addressing sin in accordance to the Law—it was a legal point. So when balanced with the full corpus of Scripture, the historical (= Catholic) understanding is most reasonable, and your group’s theology is based on one verse that is forced to be incongruous with the remainder of Scripture.