Comment by the_af

It's still very impractical though. Sniping everywhere that intelligent life might exist is very low probability, low stakes, and for what reason? You don't have any reason to kill anyone you're unlikely to ever meet. And with a weapon which, by the time it arrives, your civilization might be gone. And for what? You cannot compete for resources you cannot reach. War doesn't work like this, it requires anger and an adversary that you can meet in your lifetime.

Dark Forest also assumes aliens aren't curious and thrilled about other life existing out there. The one civilization we are familiar with wouldn't react like this. And we're talking about a very warlike civilization!