You only have "instant corruption" if the array becomes degraded before the parity gets corrected. For this reason mdadm will not assemble an array which is both dirty and degraded. I thought I had mentioned this in my original comment, but apparently not. Maybe this is the case implied in the original article, though I don't think the text really matches reality: Either there is a correct fix that is trivial, or no fix is possible.
(The only two ways to avoid corruption when a crash happens on a degraded array are 1/ to journal updates at the raid level, or 2/ use a copy-on-write filesystem that knows about the stripe size and only ever writes into a stripe that does not contain any important information.).