Direct current is much safer than AC. This is a fact. Edison proved it with his tests. Arthur Clarke and others suggested that with cold fusion generators we should go back to using DC to reduce the threat of electrocution.
No, he did not. This is a myth. His income was mainly from patents, and you cannot patent a stolen invention. The original inventor will complain and the Patent Office will revoke the patent. Edison did, of course, build on the work of others. All inventors do. For example, incandescent lights were invented about 20 years before he began working on them, by Moses Farmer and others. Farmer was not upset and did not claim the Edison stole anything from him. He had a high opinion of Edison.
If you think its so safe go and grab the positive lead on the alternator of your car.