Although your assumption may be correct, the comment is valid. The assumption is not.

I've cracked a few aluminum road frames - an older Cannondale, a Specialized M2, and a Giant TCR.

There's the concept of pushing the limits with materials. If you build something so that there are no failures then you've overbuilt it. At the same time you want to have no failures in certain parts, so, for example, I'd consider a fork, bars, stem, and steerer to be the "no failure" parts of a frame/fork.

All my frames failed in the chainstay, about the safest place for a frame to fail. None broke through. I rode all of them for a while before replacing them (a month or two). Other than some creaking, some tire rub under pressure, the frames were rideable (and raceable). In all three instances I didn't know the frame was cracked until I happened to find the crack (or a coworker did).

I've also seen some amazing steel frame failures, the most incredible a Pinarello whose top tube cracked in half. The ride noticed something wrong in the last lap of a race when his bike felt "bouncy". It should have - you could push the saddle down a good 2-3", until the bowing bike's cranks almost hit the ground.

I broke a ti axle BB (the right arm came off, reminiscent of Fignon's Campy SR ti axle failure). All materials have their limits and design limitations.

I happen to ride aluminum frames. I'd ride carbon (have in the past) but custom carbon is too expensive. Fit > Material.