We are speaking in the overall sense, in which Catholics overall believe in papal infallibility and jurisdiction, Roman purgatory, indulgences, the Immaculate Conception, if not universally, while the real comparison is btwn those who hold to the supremacy of Scripture as the wholly inspired Word of God, and those who hold that the Church is the supreme authority. Under both you have unity as well as disunity, but the type of unity is the difference.
Mormons are not Christians because they do not believe in the Trinity
Within the "E" group, there is no consensus on this most basic of topics -- Oneness Pentecostals believe in a fundamentally different nature of God from say Assemblies of God or Southern Baptists
That is a core, foundational difference
you cannot call this any form of common opinion if there is no foundational agreement on the nature of the Godhead
And Oneness pentecostals are 24 million, about 10% of the "E" denomination