Did White Virginians enslave people of African American descents because of long held, deep seated racial bias?

Yes, they did:

In 1629, Virginia's General Court ordered a general muster (gathering) of all the inhabitants (men, women and children) both Englishe (a term they used to refer to other non-English Europeans) as well as Negroes, who were perceived as a separate group. This goes beyond the belief that White culture was superior than the one of the Negroes; White Virginians had from the beginning a long held deep-seated antipathy to the African American descendants. According to 16th century English sources, there was a serious English prejudice against Africans even before 1619. The English tended to relate blacks with apes, unbridled sexuality, and with extremely un-Christian behavior. All of these ideals created a profound prejudice against Africans, and such prejudice was carried to America as well. English also believed that the skin pigmentation of blacks had implications of evil and repugnance. Therefore, White Virginians considered Africans not only as a separate group but as group of people visually, socially, and maybe biologically different, labelling them as inferior to white people. As a result, White Virginians believed that Africans "qualified" as slaves because they were different and considered them evil.