You are wrong:
Every country of the EU has a different VAT rates (
https://en.wikipedia.org/wiki/European_Union_value_added_tax). So you cannot compare the US with the EU, you have to do it for every country separately.
There are no
import taxes for computers in the EU (
https://www.zoll.de/SharedDocs/Boxen/DE/Fragen/0082_beispiele_zollsaetze.html?faqCalledDoc=289528).
There is
import VAT, but this is a zero-sum thing for companies, as they are allowed to claim that import VAT in their VAT tax declaration. Only the very last buyer pays VAT (we, the consumers). If an individual buys a computer in the USA and imports it into the EU the import VAT is of course not refundable, but for companies it is.
And then you either need to compare net prices without any taxes, or end prices including taxes:
A fully maxed out 13 inch MBP incl. everything costs in the states USD 3,246 net without any sales taxes. In Germany the net price for the same device would be EUR 3,249. With the current exchange rate of 0,9290 this amounts to EUR 3,016, which makes the device in Germany
8,33 % more expensive than in the US.
The same device with 6% sales tax in Florida, compared to the price in Germany including the 19% German VAT gives you a
difference of 12.4%.
It is not 20%.