Two friends want to spend time by themselves. They ask the third person to leave, but he clings like a barnacle. what does melancholy mean

How can we make the world a better place, specifically towards discriminated people (lgbtq+ community, people of color, people with disabilities etc.) how can we make them change their view on people they call "different"? how can we get people to love one another despite how they look or who they love or where they are from? 2-3 paragraphs ! (ᵔᴥᵔ)