Do you not lock your doors because you feel you shouldn't have to worry about people stealing your stuff because it's morally wrong to steal or do you do it to mitigate risk? Suggesting someone should mitigate potential risk is all we are talking about.
The comment I responded to was this:
>it's only fair for them to financially award people that responsibly inform them of vulnerabilities instead of easily and anonymously selling those.
That comment includes the threat ("instead of easily and anonymously selling those").
So, yes. That is the definition of extortion.