Hmmm their
blog entry doesn't mention anything about parity with MS. They just said they want to make sure the other versions don't suffer from the same or a similar problem.
Of course this doesn't mean the parity thing couldn't be the true reason.
While I don't think a parity policy is very helpful for indie developers, an indie studio can't afford to ignore an install base like the 360's. Especially after they already invested the time to create a 360 version that's nearly finished. I think there's also some Kickstarter backers that wouldn't be amused if there wasn't a 360 version.