What makes you sure your version is true, while there's isn't? They're not your friend, they're a giant, exploitative megacorp.
I doubt the security team is sitting there choosing not to patch this, given that they are passionate about security. And it's unlikely that management has told them "don't release the patch, we want the people on old OSs to suffer!!".
Most likely is that they just don't have as many resources for writing and testing the patch on the old versions, so it's taking longer.
* Rushing out a patch that introduces possible instability
Which action do you think is better for business?