The process of science is not the process of debate.
Anyone can challenge a scientist with absurd claims in a public forum, and suddenly the burden of proof rests on the scientist? Unfortunately, it seems to be the case, as "science" is treated like a thing to be attacked, instead of a process of discovery.
This whack-job needs to take the time to educate himself, and carefully research his claim before spouting off such tripe. it's an extraordinary claim, and it demands extraordinary proof--careful, long-term studies with large sample sizes and proper controls, replicable laboratory results, or some other methodology with clear results to counter the massive quantity of solid research on HIV and AIDS.
As for HIV being over-hyped, check out the World Health Organization's report on world health at
http://www.who.int/whr/en/ --the statistical annexes give charts of what people are dying from, and they're dying from AIDS.