Maybe you should stop calling him irresponsible and put yourself in his shoes:
He updated an application that wiped out sensitive data. Not wanting others to suffer the same fate, he came onto MR and posted a beware of update thread. Sure, he didn't know that it might have been an isolated case, but I'd much prefer someone do what he did than say nothing because they don't know if it's widespread.
He could have
a) Mentioned it like he did. This probably prevented a few people from upgrading for a few hours. If it was a widespread problem, it would have saved people from spending hours re-inputting all of their data.
b) Not mentioned it. If it turned out to be a problem, many people would have downloaded the update and wiped all their data because he didn't make a thread. Since it isn't a problem, there was no harm done.
The situation, as I read it, was not anything near an alarmist/irresponsible post. It was cautionary, and I thank the OP for posting it. Sure, I didn't update my SplashID for a couple hours, but the potential cost greatly outweighed the benefit of an update a couple hours earlier...