in light of the genocide in rwanda triggered by the words "crush them
like cockroaches" on the radio, what has government done to control
the potential abuse of power which the media wields?

What a bunch of racist crap.

Hmmmm... perhaps, on the other hand, it was an attempt to show how
well racist propaganda works in the media?

Australian media mogul Rupert Murdoch (now a U.S. citizen) owns Sky TV
in England. He owns FOX TV in the U.S. He owns the sole English
language broadcast network in Asia. That is an immense amount of
global influence. English soccer and American football and baseball
are the hooks to attract viewers.

Edward L. Bernays, Sigmund Freud's nephew, wrote a seminal book in
1928, "Propaganda". He was a major force in American advertising,
politics and media.

Canadian media professor Marshall McLuhan was writing about these
issues in the 1960's.

Hollywood movies and TV shows are full of messages about business,
politics, social issues and culture.

Political polling and campaign management is highly sophisticated.
Presidents starting with FDR and JFK to Reagan, Clinton and Bush are
brilliant at image projection.

Pat Robertson is a marketing expert as is Jerry Falwell.

There are library shelves full of books and periodicals on this topic.

Just a note: The comments above mentioning racism refer to another
comment which has since been removed. They do not refer to the
question itself.

Just FYI, the Rwandan radio station that broadcast the incitements to
violence, RTLM, was owned and controlled by government officials.
Privately owned media have historically been less prone to abuse of
power, extremism, and violence than media outlets run by autocratic
governments.