Adams, like most men of his age did not believe in racial equality.
You Can’t Tell the Story of 1776 Without Talking About Race and Slavery
https://time.com/6077468/united-states-1776-racism-slavery/
John Adams, Slavery, and Race: Ideas, Politics, and Diplomacy in an Age of Crisis
https://academic.oup.com/jah/article-abstract/106/4/1055/5741509?login=false