Melissa, I know very little about the history/current programming of either BET or MTV, and IMO those subjects are beyond the purpose of this discussion. However, here is some information that I found from a cursory Google search:

"BET was launched in 1980 by media entrepreneur Robert L. Johnson. Having gained experience as a lobbyist for the cable television industry in the late 1970s, Johnson saw an opportunity to reach African American audiences through a cable TV channel. BET originated with two hours of weekly programming in 1980 and slowly gained viewership throughout North America and the Caribbean. Music videos were an early staple of BET programming, as were shows that targeted a youthful audience, but the network broadened its focus to include political and issue-oriented programs, comedy showcases, talk shows, and sports, among a wide variety of offerings. Having established BET as a successful niche media company, Johnson launched it as a public corporation in 1991. BET was listed on the New York Stock Exchange until 1998, when Johnson and other investors gained private control of the firm. In 2000 Johnson and his partners sold BET to Viacom Inc. for $3 billion. The network reaches about 70 million households. BET's affiliated businesses include book publishing and event production."

http://www.britannica.com/blackhistory/article-9399722

**

Rewinding 25 Years Of Mtv History
Publication: Billboard
Date: Saturday, September 2 2006

The following is a timeline of notable milestones in MTV's history compiled from information provided by MTV.

1981
MTV debuts Aug. 1 with a clip of the Buggles' "Video Killed the Radio Star." The channel confirms the concept of cable niche programming, reshapes music marketing and becomes a symbol of youth culture... The channel ends the year with 2.1 million subscribing households...

http://www.allbusiness.com/retail-trade/miscellaneous-retail-retail-stores-not/4565907-1.html

Also, visit http://en.wikipedia.org/wiki/MTV

..."MTV's pre-history began in 1977, when Warner Cable (a division of Warner Communications, and an ancestor of Warner-Amex Satellite Entertainment (WASEC)) launched the first two-way interactive cable TV system, QUBE, in Columbus, Ohio. The QUBE system offered many specialized channels, including a children's channel called Pinwheel which would later become Nickelodeon. One of these specialized channels was Sight On Sound, a music channel that featured concert footage and music oriented TV programs; with the interactive Qube service, viewers could vote for their favorite songs and artists.

The original programming format of MTV was created by the visionary media executive, Robert W. Pittman, who later became president and chief executive officer of MTV Networks.[2] Pittman had test-driven the music format by producing and hosting a 15-minute show, Album Tracks, on WNBC in the late 1970s.

Pittman's boss, WASEC Executive Vice President John Lack, had shepherded a TV series called PopClips, created by former Monkee-turned solo artist Michael Nesmith, the latter of whom by the late 1970s was turning his attention to the music video format.[3] The inspiration for PopClips came from a similar program on New Zealand's TVNZ network, Radio with Pictures, which premiered in 1976. The concept itself had been in the works since 1966, when major record companies began supplying the New Zealand Broadcasting Corporation with promotional music clips to play on the air at no charge.

Additionally, in the book The Mason Williams FCC Rapport, author Mason Williams states that he pitched an idea to CBS for a television program that featured "video-radio," where disc jockeys would play avant-garde art pieces set to music on the air. CBS cancelled the idea, but Williams premiered his own musical composition, "Classical Gas," on the Smothers Brothers Comedy Hour, where he was head writer. The book in which this claim is made was first published in 1971, ten years before MTV first came on the air."

-snip-

FWIW, I have yet to find any information online about when the first music video by a White artist/group was first aired on BET.

If you find that information, I'd appreciate you posting it to this thread though in my opinion that information is tangential to the thread's topic.