In many cases, without publishing the keys to make it PAINFULLY obvious to everyone that the vulnerability exists, large companies can spread disinformation and influence public perception that the vulnerability is minimal or doesn't really exist outside of a special case/etc.
In this case, VW is very obviously not planning on updating things, fixing the vulnerability, or addressing things. The vulnerability and the codes have been available on the internet for YEARS without a proper response from VW or a bulletin or other addressing of the issue (and obviously no 'fix' either).
This is one of the key points of the 'responsible disclosure' debate: many companies DONT CARE unless they have to, and will just sit on things indefinitely. With all this publicity, I bet VW addresses this pretty significant vulnerability sooner rather than never now.
Do you disagree with free speech being used to publish de-css or the blu-ray decryption keys? If your security depends entirely on a single key being not discovered and re-used (because you have no way of changing it, for example), you really have a horrible security model. If you're selling that security to people, and it's really not effective at all for it's purpose, then how much different is that from false advertising or even fraud (given that you KNOW that it's not effective, or has already been easily subverted).