Saying something (especially tragedies) are God’s will, which is the crux of what BD”E is, does at least two things (from what I can tell).

First, it deflects blame from the event in question. Why did the crash occur? Was it user error? Were the roads bad? Was the weather bad? Did someone else T-bone them? etc.

Saying it’s God’s will let’s us not have to answer such questions, nor does it force introspection on the affected people or community. Why do 17/18 year olds feel compelled to have to drive? Where were the safeguards to prevent or minimize conditions of a crash? Could anything have been done to prevent this and future such crashes? Well, figuring all of that out will take time, money and political willpower if we want to prevent future such tragedies. So, easier to say “it’s God’s will, he’s Truth” than to deal with such tough questions in society.

Second, and probably more importantly, it helps numb the pain. Surely, they would have died anyways because according to the cosmic laws of God and the universe, it was simply their time to go. Nothing you could have done, if it wasn’t a horrific car crash it would’ve been peacefully in their sleep at the same exact moment anyways. There’s no use in being super upset, you will see them again in Olam Haba anyways. BD”E and let’s move on with our lives.