In truth, the bereaved will surely be angry at the bombs dropped by party X, but at the same time understand the impatience of party X towards government Y that oppressed both you and your dead family.
There is much more room for regret: regret of not openly supporting saner voices, regret of taking what seemed to be the least personally risky path, until the final conclusion proved otherwise...
Allowing your government to rot to the core and pretending citizens do not carry any responsibility is what leads to things like Nazi germany, Iran, etc...
The War against Iran is the most stupid conflict I have seen instigated by the U.S. Your quote of "regret of not openly supporting saner voices" should be directed at the U.S. & Israel since they launched this war. There was no cause for it except for distracting from the Epstein files and any blackmail material held by Israel.
> Hah, wishful thinking that. If your family is wiped out by invaders, you will vow vengeance till either their death or yours.
And then changed the supposed vengeance across oceans into local vengeance when asked for evidence.
You don't go to war against a nation with a happy population: it generates a whole nation of enemies.
If you only go to war against a nation with unhappy populations, you will probably leave them as unhappy as you found them, but hopefully they can start taking matters in their own hands...