To homogenize is to make something the same, or similar. When dairies homogenize milk, they mix it so the cream isn't separate from the rest of the milk, but instead all the liquid is the same consistency.
When food processors homogenize milk, they make it uniform or alike, and when circumstances homogenize a neighborhood or school, the result is a group of people who generally all resemble each other. You might complain that high rents and gentrification in your town have homogenized it, leaving only wealthy professionals able to afford to live there. The Greek root, homogenes, means "of the same kind."