This is happening because unlike almost every other developed nation the US has a worldwide tax system. Almost every other nation has a territorial tax system. The rest of the world with their territorial system taxes income earned within that country, the US rather taxes income worldwide, regardless of where it is earned.
For example, if a British company earns income in Germany, its pays German taxes on its German income. But if a US company earns income in Germany it pays both German taxes and US taxes.
This is not about avoiding tax on profit earned in the US, after the inversion companies continue to pay US taxes, they just don’t pay taxes on income earned outside of the US.
For example, if a British company earns income in Germany, its pays German taxes on its German income. But if a US company earns income in Germany it pays both German taxes and US taxes.
This is not about avoiding tax on profit earned in the US, after the inversion companies continue to pay US taxes, they just don’t pay taxes on income earned outside of the US.