the most generous reading of your arguments is that you are philosophically defeatist

That's probably a fair assessment.

But I feel like the core of my argument remains: I'm not disputing that MS or Google or Amazon or Apple services are sold to people and orgs who use them to commit evil. Of course they are.

But these aren't munitions. They are general-purpose computing products being turned to evil outcomes by bad actors. The article, for example, cites Microsoft's open-source LAVENDER, which is a general purpose image and video analysis tool for AI. Describing it as:

‘Lavender’, an AI-powered system designed to identify bombing targets

This simply isn't true. Somebody in the Israeli military used LAVENDER to process video data to identify bombing targets, like somebody might use a hammer to smash someone's head in. The articles you cite are full of rhetorical tricks to imply that Microsoft corporate had some hand in the decision making, but it's genuinely all "well the Israeli military has some Azure servers, therefore Microsoft killed people".

Which militaries should Microsoft (or Google or Apple or Amazon, etc) be allowed to sell products to? Who makes that determination? A cohort of employees or consumers? NGOs?

If government makes the call -- distilling a public consensus on the matter, one hopes -- then I can see some reasonable way to approach this question.

EDIT: Details on LAVENDER:

https://www.microsoft.com/en-us/research/publication/lavender-unifying-video-language-understanding-as-masked-language-modeling/