[LexBaird]

They themselves are separating themselves from Evangelical Christian churches and doctrine. It follows that they are not, therefore, Christian.

You commit the basic logical fallacy here of "begging the question". To accept your conclusion, one has to accept your premise that pre-defines Christian to fit your conclusion. When the framing of your argument presupposes that "Christian" is to be defined as "those who follow Evangelical doctrines", then naturally you come to the conclusion that non-Evangelicals are not Christians. But, of course that would also make other Churches with non-Evangelical doctrines, such as Catholic and Orthodox, not Christian by your definition.

What truly follows from your argument is that Mormons are not Evangelical Protestants. I doubt Mormons would argue with that.

[Theo]

Would Mormons feel free to join either Catholic or Orthodox churches? No, because Mormons don’t consider their doctrine compatible with theirs.

I only referenced Evangelical Christian churches in my comment because that’s my experience.

Mormon doctrine is incompatible with all traditions of the Christian faith, something they concur with in their rejection of all Christian faiths.