That's not true. Take a look at the Wikipedia page for it. (emphasis mine)
Eugenics (/juːˈdʒɛnɪks/; from Greek εὐγενής eugenes "well-born" from εὖ eu, "good, well" and γένος genos, "race, stock, kin")[2][3] is a set of beliefs and practices that aims at improving the genetic quality of the human population.[4][5] It is a social philosophy advocating the improvement of human genetic traits through the promotion of higher rates of sexual reproduction for people with desired traits (positive eugenics), or reduced rates of sexual reproduction and sterilization of people with less-desired or undesired traits (negative eugenics), or both.
Eugenics has even happened numerous times in America, mostly in the late 19th and early 20th century, but most people don't know about that. It didn't always involve killing people, but it
did involve compulsory sterilization and euthanasia programs. Nobody knows about all of the awful things that America does because there's not a snowball's chance in hell that any of it would ever be allowed in history textbooks.