As for the attack happened to BCH during its upgrade, Emin Gün Sirer, the professor at Cornell University, commented the issue and post a string of tweets, saying that someone spent months sitting on this bug and chose to exploit it during a scheduled upgrade. It's pretty juvenile, but also, a great reminder that this is a space with byzantine actors, and people must pay close attention to software correctness, according to him.
He summarized his views as follows:
1. The attacker spent a lot of human resources;
2. The patch was quick and painless;
3. A temporary hiccup is small price to pay for progress.
Click 'Read More' for his tweets.