There's a couple that do. Similarly certain Baptist and methodist sects heavily emphasize going to Europe and converting Catholics and Orthodox practitioners
I've always been the guy who does consider Mormons christians. I don't think it matters that they're non trinitarian. That just makes one a nontrinitarian Christian. But more and more, with some family having converter and some friends, I'm more leaning towards them being a full blown cult, in the colloquial sense of that word. A Christian cult, but a cult. They're huge which is really the only reason they're not considered a cult. If their membership were 1700 instead of 17 million, pretty much nobody would hesitate to call the group headed by a charismatic "prophet," that initiates members in a secret ritual, demands the wearing of sacred underwear, and teaches that God is an alien who will make you king of a planet when you die a cult. So, yeah, Christian. But a Christian cult.
A lot of Christians groups don't consider Mormons to be Christian. They don't believe in the Holy Trinity, which is a fairly core belief of most Christians.
Like in a sense, Christians are just Jews with an extra book. Mormons are Christians with an extra book. Are Mormons Jews?