> You cant as a company in Denmark offer a normal employment contract to someone in Germany. You need a legal entity in both countries.

This is the same in the US, if you hire someone in a different state you need a legal entity in that state, and there may be different local laws around taxes, health insurance, pay, etc.

> There's also still european xenophobia and racism (ie not hiring someone because of their nationality).

Same in the US.

It's true that there are a lot of different languages, but I don't understand how you get from there to "Europe isn't real". I don't really know what you mean by synergies, but EU countries can easily trade with each other and citizens can freely travel between countries, so one country's growing economy certainly benefits residents of other countries.