Are there any justifying reasons for the existence of the Seventh-day Adventist Church? Yes; they are just two, and they are found in the name.
This church was not raised up to preach justification by faith. That was the work of Martin Luther. It was not raised to preach good words of those justified; John Calvin did that. Our message is not one of baptism by immersion; there is another church that brought that message...the Baptists.
Truth as it exists in Jesus Christ is His Word. And in His Word (the Bible) these truths are like pearls strung on a red thread that reaches from Genesis through The Revelation.
Adventism is a movement that arose from people who left the churches that existed in the 1830's and 40's. They left because there was a worldwide awakening in the hearts of men and women who believed that Jesus was returning in 1843 or 1844. They were mistaken, and the message that tasted sweet as honey was bitter in their stomachs [Revelation 10:9]. World wide, men were preaching the return of Christ; in the Americas North and South, in Europe, and elsewhere. This was not just William Miller [not a Seventh-day Adventist as they did not yet exist] preaching in New England.
So what then is the message of Adventism, and is its existence justifiable and defensible? Yes! (But of course I would say that).
Let me explain: Seventh-day Adventists are an annoyance; first to the Catholics and then to Protestants because the message is one of the holiness of the whole Law of God...ten Commandments...and the Sabbath in particular.
Protestants and Catholics are very happy with nine out of the ten "Words." After all, that's 90% and that's good enough for a passing grade in any class...except for the fact that it was the I AM who wrote them. [See Exodus 3:13 and 14, and, John 8:58].
It's really very simple for Protestants, but not for Catholicism, because every honest preacher and priest knows full well who it was that "edited" the Ten Commandments by tossing out #2, rewording #4, and dividing #10 in half.
In a nutshell...as opposed to a nut case...here are the two reasons the Seventh-day Adventist Church exists: 1). To remind the world that Jesus Christ created the Sabbath (1500 years before the first Jew), that He is Lord of the Sabbath, and that He expects the world to Honor Him as Lord of the Sabbath [Matthew 12:6-8; Revelation 14:6, 7] and 2). To warn the world of Christ's soon, glorious, obvious, and spectacular return [I Thessalonians 4:16-18].
That's pretty much what we're about, and just as Luther sang an essentially one-note song about Righteousness by Faith, our two-note song is about the Sabbath and Christ's imminent return.
(Maybe if we too followed the 90% obedience rule we would be more acceptable in the religious world at large...maybe. e.c. admitting thievery of thought from r.s.