they are standardized in the EU actually. Standardization started in 1977. but since 2007 stuff got more serious. The real problem is that each country have a different rate, but for the rest, it's quite smooth. Tax issues across countries in Europe are often easier than in the US from what I read around.
One issue I have with the article is asking Amazon, a notorious tax dodger, to enforce some tax rules on others doesn't seem like the right way to go.
TLDR There are too many different rules and regulation regarding how, when, at what rate and why and on what VAT should be collected and these local regulations have some many caveats that it very difficult to be 100% compliant locally not to mention globally within the EEA market. Add to that the fact that you have various VAT exemption rules that govern when and how businesses and individuals can become VAT exempt (e.g. small businesses, non-profits, charities, disabled or terminally ill individuals, etc.) and you get a steaming pile of horse shit.
One issue I have with the article is asking Amazon, a notorious tax dodger, to enforce some tax rules on others doesn't seem like the right way to go.