The correct answer to this open question is the following.
Unfortunately, you forgot to include the name of "those countries" that receive the waste from the United States. Without the names, we are limited to fully answer.
However, trying to help you we can comment on general terms based on our knowledge of this topic.
Many times the waste going to underdeveloped o poor countries instead of saying in the United States for recycling is because it is cheaper for the United States to send that waste abroad to those countries. Another reason is that environmental laws in the US are stricter than in other countries, so US industries have to invest more money to comply with United States environment regulations. So these industries prefer to pay to other recycling companies abroad.
In those other countries, legislation is not as strict as in the US or sometimes environmental legislation is non-existent. The problem is that in these countries people, civilians, suffer the consequences.
