Maybe it does push M$ to fix problems, however, it also potentially a lot of computers at risk. For highly technical people like those of us at this site, a risk like this is something that we are able to easily mitigate.
However, there are many people out there who simply do not possess the technical skills to either ward off or remove a threat from their PC - whether we like it or not.
I am not defending M$. Personally, I think they are an exceptionally arrogant company - maybe equally arrogant as crApple.
If anyone exploited a hack made public, it really would not be M$ that suffered, it would be those people who had their computers attacked, and we all know that due to EULAs, there would be no recompense for those owning attacked computers. However, I could see someone suing anyone who made an exploit public knowledge.
To me, its common sense - let M$ know privately regardless of whether you are treated like a terd or not. Wait a month or two - then make it public. As I see it, the burden would then be on M$ if they had not fixed it yet as they were informed of the exploit.