I do feel that most times when the US is involved in domestic issues in other countries that it is for goodwill and human rights. Of course there are exceptions to this but in general I think that most reason for involvement is genuine goodwill and to protect human rights.
I believe the US, along with other of the world's super powers, cannot sit idly by when there are atrocities being committed in other countries. I think when the US or the UK become involved, it is a sign of goodwill plus human rights interests. I do not believe it is solely economic and political interests that prompt our involvement.
When the US is involved in domestic issues in other countries, it is a sign of American goodwill. Some domestic issues in other countries do not cost the United States much in either direction, such as helping to stabilize the area of homelessness. The U.S. is aware that one of its international roles is that of helper.
History shows that the US has largely ignored human rights violations in countries that have little to no economic or strategic value to itself. The mistreatment of women in Nigeria, for example, has received only token, largely private, activism from the United States. However, the mistreatment of women in the Middle East has been cited as cause for US intervention in many military actions. The situation is much worse for women in Nigeria, but it has little in the way to offer the US financially. The countries of the Middle East, however, do.
I do not believe the United States has any business being involved with the domestic issues of other countries. I believe when you see this happen, it is generally because America is doing so to protect their own economic and political interests. While America is interested in goodwill and human rights interests, our politicians don't usually get involved with such efforts unless it means a kickback for them in some way.
Although the work that many government-associated agencies do is wonderful, the number of issues in our country today goes against the idea that they are doing it out of the goodness of their heart. I fully support the work done for other places in the world, but because of their focus on developing countries, it is apparent that the U.S. is hoping that these countries will aid them in the future once further developed.