Hetzner is just an example - you can get cheap dedicated boxes with gigabit uplinks all over the world. And in this example it's not even important what latency the server has, since it was only feeding Cloudflares CDN with data.

The reason Europeans tend to favor European service providers generally has to do with strong data protection guarantees and some level of protection against foreign surveillance. In practice a lot of European companies still use US services or at least services provided by US companies -- Troy Hunt is Australian and uses Azure from Microsoft, so this isn't just a thing Europeans do either.

I'd love to hear your reasoning why people who aren't European would prefer to avoid European service providers.

OVH then? They have similar offerings, unlimited traffic, multiple datacenters to pick from.

Hetzner launched in the US by now