Why does one generation have to experience such terrible cataclysmic judgments?
That generation experiences such cataclysmic judgments because it brings to a head what previous generations had been sowing. Scripture declares God's judgments are true and righteous, and He visits iniquity down to the third and fourth generation; this is simply God's way.
Les explains that people naturally think God is unfair and ask why this one generation must face such terrible cataclysmic events. His answer is that this generation is bringing to a head everything previous generations have been sowing the seeds of. God has always done this, though we cannot always reconcile why He brings judgment and chastisement on a generation for what three or four generations back were guilty of; it is just the way God does it. The context also notes the Ten Commandments' warning that God visits iniquity to the third and fourth generation. The angels declare that those who shed the blood of saints and prophets are worthy to drink blood, and the altar affirms that the Lord God Almighty's judgments are true and righteous. The fourth angel then pours his bowl on the sun to scorch men with fire or intense heat, and Les points out that Revelation fits with the Old Testament, such as Isaiah 13.