Most work isn't directly involved in the kill chain. That's a ridiculous dismissal.

I mean the mindset as “crucial to your self esteem to believe your work is a net good for society”

Because ‘net good’ is debatable, your beliefs will clash with others who think it is not a ‘net good’ regardless of the work.

E.g. people involved with sugar production have probably caused more integrated harm than those making missiles. This is especially true as obesity passes 50% of the population.