The function of the "shouting and cursing" is to draw attention. If Linus had used mild language, it wouldn't be on Hacker News and we wouldn't be talking about it. When Linus rants, it's always something worth ranting about; it's a powerful shaming tool to enforce good behaviour in a world where there's little other leverage.

And in the unlikely event that your theory regarding undisclosed vulnerabilities is true, this will certainly make them think twice about leaving Linus out of the loop again, no?