It is the logical outcome of a democratic culture to help others. There are others overseas who do not have the resources or opportunities that we are afforded here. Or they are disadvantaged in other ways. The most salient problem is poverty, followed by lack of education. These problems prevent problems from reaching their potential, and from being part of the larger world.
Democracy is about all of the people being part of their society, and all having equal political opportunity. This ideal is compromised if individual people cannot make use of their opportunity, cannot make use of their political rights, because of disadvantages in their life that they have absolutely no control over.
To help another human being is to achieve several things. Keeping an otherwise starving person alive is reason enough to give offer support. To help them develop as a human being, through education and good experience, is another. To help achieve equality in the world is a worthy long term goal.
Giving to charity is helping other human beings to become an equal part of the world we live in.