Anyone who truly knows Christ as Savior has their faith built on His death and resurrection, but we also have the "blessed hope", as He described the harpazo, or catching away, of His church. The doctrine of the Rapture is in the same book as the gospel, and was written by the same God. It is just as much factual as Jesus' death on the cross, and will happen just as sure as Jesus' death on the cross happened.
As for people getting hostile over disagreements, I really haven't seen that. I see Bible-believing Christians get passionate about defending the Scriptures, and therefore Jesus Christ, from unbelievers who attempt to deny Scriptures and, by doing so, deny Christ. It's about God's Holy Word, and whether or not it is absolute, inerrant truth.
Christians get "hostile" and are supposed to get "hostile" when their Savior is under attack from those who will deny Him by denying His Word. It's not about disagreement - it's about defending the One Who paid an incalculable price to rescue us from the consequences of our rebellion against Him and Who gave us the opportunity to be reconciled to Him and to be forgiven and to have the gift of eternal life.
It's not about simple "disagreement" at all.