You're reaching.
First, there's no indication in the article that the researchers or Wired presented the remote windshield wiper hack to the car's manufacturer and that they subsequently ignored it.
Second, there is plenty of indication that the exact opposite is true. The remote windshield wiper hack occurred this June, whereas the article states that they've been working with Chrysler on this for nearly nine months and that Chrysler released a patch prior to the publication of this article.
Third, the Cadillac anecdote isn't really relevant here. For starters, it looks like they were contacted by Wired, not the researchers, so it's unclear whether they were contacted before the dangerous freeway demonstration took place. And while the mention of the newer model is a bit odd, the statement also mentions devoting more resources and hiring a new cyber-security officer, making it unfair to characterize it as a "whatever" response.
Sure, it'd be nice if Cadillac was a little more proactive here, but keep in mind that the researchers hacked a Jeep (made by Chrysler), NOT a Cadillac (made by GM). The researchers think the Cadillac is also vulnerable based on its feature set, but absent a specific flaw to patch and given the short amount of time since the initial demonstration (less than two months), it's unclear what GM is supposed to do here.