Unfortunately it's not that simple. "Your systems" is the tricky part. Companies use a number of external providers for storing customer information and that's hard to say yes to.
And then there's the issue of global infrastructure: do you have a global CDN? If yes then you probably need presence in many external countries.
But it gets better: if you have a global CDN and the government just doesn't use it, you still have presence in other countries or use an external provider, so you need to abide by their laws. And how do you provide 24x7 engineering support without an office outside of the EU whose employees have access to the systems?
Things would potentially work if a certain company was dedicated to serving the EU government sector and didn't have any other customers. But in reality that's not the case and things get tricky. If anything, it's an uphill legal battle at global scale and small companies can't afford to fight it. That's the ugly truth.