In a sense, I get where he's coming from. By providing this information, he is actually helping AV people to fix weaknesses in their software.
"Security through obscurity" doesn't work; if he can find these weaknesses, so can others. By shining a public light on the vulnerabilities rather than keeping them in the dark, he can actually help make the situation better.
However, having said that...most white-hat security people will at least notify the AV vendors of weaknesses a month or so before they publish the weaknesses publicly, so as to give people time to fix those weaknesses. By not doing that, I think he's making a mistake.