The US system is protected by a strong constitution. Others around the world are not so lucky. The point is that these email records are permanent not ephemera

The US system is protected by a strong constitution. Others around the world are not so lucky. The point is that these email records are permanent not ephemeral. And therefore they have to be viewed in a more nuanced light. For example something does not have to be a crime to come back and bite you. This could be a job losing issue, an issue that prevents you from running for public office, or even a blackmail issue. For example (and I'm not stating my position on this issue) opposing gay marriage used to in the US be an acceptable moral stance. According to what happened to Brenden Eich this is no longer the case and emails on the topic someone sent 10 years ago might come back to hurt them today.