People who thinks that what happened is unacceptable needs to understand that Apple must receive a lot of these types of call every week. What would you do if someone send you multiple messages saying that they found a major issue _without even detailling anything_ while this person actually wants you to give them money for what they found (that they still haven't disclosed any information about it)? I'm sure the majority would ignore these calls unless some details were shared about the issue.

I am not surprised about what happened at all. There is an argument that can be made about the fact that it took Apple so many years to finally implement group video call that they could take a little bit of time to do it right but other than that, I don't see how Apple could have prevented a bug that a person wasn't willing to disclose without having money first.