After what happened to Charla Nash, why is anyone in the U.S. allowed to keep a chimp at home?

It is well known that chimpanzees are physically stronger and fiercer than human beings are. In light of this knowledge, why are people allowed to keep chimps in their homes where they can potentially escape and hurt or kill innocent people? A home is not a zoo, so a homeowner should not be allowed to keep a chimp at a private residence in a residential neighborhood. Charla Nash was left blind, disfigured, and without hands after 'Travis' the chimp, a neighbor's pet, freaked out for no reason and brutally attacked her. I can't believe there has been no legislation banning the private ownership of chimps in residential neighborhoods following this grisly attack.