In Act II Scene 1 what is so controversial about the house Mama bought in poem raisin sun?

There seems to be a misunderstanding. The play you're referring to is "A Raisin in the Sun" and not "poem raisin sun". In Act II Scene 1 of the play, the controversial aspect of the house Mama bought is that it is located in an all-white neighborhood. The white residents are not happy about the prospect of having an African American family move in and try to block the sale of the house. This highlights the racial tensions and discrimination faced by African Americans during that time.