If lashon hora and sinat chinam (hate with out reason) could destroy the bait Hamikdosh/ Holy Temple, then certainly they can prevent its rebuilding.
*Remember that Heavenly judgment is initiated by lashon hora on this world,.
*While anger and insensitivity destroy the fabric of one’s soul, lashon hora is in a class by itself.
*No other sin has as many negative commandments related to it.