Just because you choose not to work on a project due to personal reasons doesn’t free you of the unethical or immoral things the company you chose to work for does. And if you actually believe it does then it only supports the argument that these firms have found a way to act immorally in the pursuit of fees while making sure their staff don’t become too demoralized. They know there will always be someone to take on the work because the workforce is highly fungible so they don’t care either way, and if anything makes them look compassionate to their employees which benefits them.