She was banned from the US because border control are arbitrary, intrusive, judgemental, prejudiced and like the fact that they have power over people who have no rights in that context.
Also, in a lot of countries, being a border person is one of the best jobs available -- status, contact with foreigners, and a conscious decision by the government to put a good face forward by picking good people.
I've visited about 100 countries or autonomous regions, and I've never had a bad border experience in any country. The worst thing has just been getting visa in advance vs. visa on arrival, and in the case of Belarus, previously-restrictive policies which were loosened and a lot of people didn't know about it (transit via Minsk airport now doesn't require a visa)
The only places with on-paper bad border controls for US people seem to be otherwise-decent countries which are trying to apply reciprocal pain to US passport holders -- Brazil being the best example.