You can't argue that one religion is a cult over another. They all are cause death on a scale that nothing has even touched yet. The crusades are a unholy war that left everyone dead in its wake. The second coming of Jesus Christ isn't coming, unless some nut job steps out of the shadows.
Adventism is not a cult. The Adventists are a prime example of a denomination with some outrageous claims, but still holding to Christian truth at its core. They have historically had some biblical questionable stances on those issues such as the Sabbath, the Old Testament law, annihilation of the
wicked, and investigative judgment.
No Adventistm is not a cult. The same question can be asked for any religion or belief. Just because there is a strict following or rules that followes must abide by does not make a group a cult. If people don't believe in the teachings they should not join or be a member.
An actual cult is usually a small group where one person is worshiped over the others. Adventism has been around for years, there's a large following, and they don't have a singular leader that everyone worships. You can't call something a cult simply because you don't like their principals or ideas, it doesn't work that way.
No, Adventism is not a cult, because they primarily follow the tenants of Christianity. They have some unique views on the afterlife, specifically whether people sleep until they second coming of Christ. But other than that, they basically believe the same things that most other Christians believe. They are a denomination of Christianity, more than they are a cult.