Even if chess.com had found and patched this bug ahead of time (which they may have since the CEO has admitted he's clueless about this tech stuff), as I understand it owners of 32-bit iOS devices would've had to update their software by downloading the patch directly from chess.com. No auto-update via the App Store anymore for 32-bit apps.
That statement is untrue for so many reasons:
1. As of right now the current OS still supports 32 bit apps and 32 bit phones and iPads. The current OS supports the iPhone 5 and 5C.
2. Apple does require app developers to submit 64 bit versions of new code but they are perfectly capable of submitting a fat binary that can support iOS versions back to iOS 7 - released back in 2013.
3. The App Store also allows you to download older versions of current apps when the newest version doesn't support your hardware. This supports goes back to iOS 5-released in 2011. I can confirm this. I did it earlier this year with a circa 2010 1st gen iPad.