That actually supports the point that people aren't acting under purely financial motivations. If the guy was purely following financial motivations, surely he would have chosen to sell the vulnerabilities to the shadier side of things. Instead, he dumped them publicly, burning their value while amplifying the "fuck you" factor to Microsoft.

Ignoring reports, or just fixing the vulnerability without acknowledging the work put in by a researcher, is rude and invites rudeness in return.