That's totally not true? Many people signing this letter specifically worked on the project before they knew it was going to be used for warfare. Now they are d

That's totally not true? Many people signing this letter specifically worked on the project before they knew it was going to be used for warfare. Now they are demanding a say in whether the multi-purpose product will be explicitly sold for warfare or not. If you ambush people with a reveal that they were actually working on military tech you can't expect them all to be happy about it. That's very different from taking a job offer, showing up to work, getting told 'we're making military tech' and saying 'OK'. HoloLens is an existing product, the result of a very large amount of engineering and research. Many of the people who contributed - perhaps even pivotal, highly-compensated employees - were definitely not aware that it would get sold to the US military, even if it's not a big leap to suggest that they might be a customer.