This is a good time to point out that a significant chunk of the population isn't opposed to working for the military, for ICE, or for defence contractors who make weapons; they don't view that work as unethical. Moreover, the origin of Silicon Valley, and indeed the entire internet, is DARPA contracts and weapons manufacturing.

Any oath would either not be taken by those people, would be watered down so far as to be meaningless, or would require the entire industry to refuse to make weaponry. The first and second are ineffective and the third is ludicrous.