No. If he had started something about Oracle, what would have happened to Oracle? Some redditors and HNers would seize the opportunity to complain about how horrible Oracle is and then everyone would forget about it a few days later. On the other hand, what would have happened to Kawaguchi? Some potential employer could see him complaining publicly about one of his former employers and decide that it's a bad idea to hire him.
In all, there's little good that would come out of it and a ton of risk for Kawaguchi.
That is why I emphasized the word _let_. He doesn't have to editorialize their actions and responses. Those speak for themselves. Just share them on his blog -- he is not complaining, he is just communicating to the open source community the state of the Jenkins project. Let others comment and let Oracle damage its own image.
> what would have happened to Oracle?
Well eventually the same thing that happened to SCO ;-)
They are losing credibility in the PR domain even more. This is not directed towards the general public or even Oracle's corporate customers, but towards the hackers, sysadmins, and other tech workers. The opinions of those people matter however, and eventually they will be consulted by those that make purchasing decisions. A general mistrust and dislike of Oracle will take its toll.
For a while they had a Unix some wanted and nobody thought at the time that there will be a free better Unix variant one day. Then GNU/Linux came along...
In all, there's little good that would come out of it and a ton of risk for Kawaguchi.