I'm not sure where the "delay tactic" thing is actually coming from, nothing in the post provides any indication they think to ship without DX support, all he's saying is that they want to eventually drop it for Vulkan, in a statement meant to address the DX12 question.
Speaking as a software engineer, this post just seems sensible and like no fuss. They've committed to Windows and Linux support, and adopting Vulkan allows them to do that with a single renderer instead of having to maintain two (DX and OpenGL). It's the one API among the new-gen ones providing that platform coverage. Along those same lines you'd then want to eventually drop the DX renderer. The end result is that you're on a single renderer on all your platforms, which requires the least amount of maintenance effort and synchronization churn. It's basic good engineering and the same decision is made probably every day by others currently. I agree with his assessment of the costs involved (going Vulkan vs. DX12 is similar, DX12 doesn't fit the platform support requirements) as well.
If anything, it's good news that there's some evidence of competent engineering/reality-based decision making over there.