Third secret of Fatima was believed to be apocalyptic...hence doom and gloom. Catholics must do this or else...
Well, there is little doubt that the Third Secret says about great apostasy in the Church and divine chastisement killing large portion of mankind - the evidence is overwhelming. This is why we have to take it very seriously and strive towards Consecration of Russia.
However, you might be on to something - many Trads are obsessed with private revelations to a degree that it becomes central point of their faith. If your Catholic faith rests primarily upon private revelations rather than solid catechesis and Catholic dogma, there is definitely a problem there, and if the children get the same mindset they don't have a solid foundation for staying Traditional Catholics.