Curious about free visas, as EU citizen in 2018 we had to go through full ESTA US visa approval process just to have a freakin' connecting flight in Miami to So

Curious about free visas, as EU citizen in 2018 we had to go through full ESTA US visa approval process just to have a freakin' connecting flight in Miami to South America including paying for it, nothing free. Its due to badly designed Miami airport compared to literally anywhere else in the world I've been, that you can't connect within 'safe' restricted zone after security checkin. No, you basically need to exit airport with all security involved (walk around checkins, go outside if you want) to get to your next flight, and walk throught all security again. At least luggage was transferred automatically, but most airports in undeveloped countries can manage that too.