>If I see something heading toward failure, I let people know they may want to consider a different approach. That’s it. There’s no need to be harsh or belabor the point but it’s better to speak up than to quietly watch a train wreck unfold.
Yes, it seems cruel and also counter to ensuring the org succeeds. Your perceived ability as an engineer might go up if your colleagues fail, but your colleagues failing when you knew a possible way for things to go better is harmful to your org's goals and culture. It only takes a small few failures for the bar to be lowered to the point that you yourself may not want to work there.
Even sometimes when other people's projects are NOT your problem and they aren't seeking feedback, sometimes you SHOULD make their flaws your problem if it is of crucial importance to your org. Knowing when you should expend your energy on an initiative like that is in itself a mark of seniority.
The blog itself mentions this a bit.