This probably echoes "why-G-d-didnt-give-adam-chance-to-repent".
I'm trying to empathize Dor Hamidbar and try to imagine how would they feel, doomed by G-d Himself to die pointlessly in the wilderness in the next [tens of] years without parole. That must have been harsh! (Num 17,29):
בַּמִּדְבָּר הַזֶּה יִפְּלוּ פִגְרֵיכֶם וְכָל־פְּקֻדֵיכֶם לְכָל־מִסְפַּרְכֶם מִבֶּן עֶשְׂרִים שָׁנָה וָמָעְלָה אֲשֶׁר הֲלִינֹתֶם עָלָי׃
In this very wilderness shall your carcasses drop. Of all of you who were recorded in your various lists from the age of twenty years up, you who have muttered against Me,
Why didn't all benevolent and merciful G-d give them a chance to repent?