I wonder if it was geolocation? Anthropic is based in SF, the author seems to be based in Munich, and maybe they're not open to hiring people who aren't based in the US right now? Given the state of US visas right now, this wouldn't shock me.
My company, which is significantly smaller, hires people in multiple countries across the world. You don't need an office to hire (I am sure there so exist countries where you do, but I expect they are the minority).
