There are many things that would be material events or material developments to shareholders. For most, regular reporting requirements in Quarterly and Annual reporting documentation take care of them, and for a narrow set of developments deemed highly consequential, by rule, one would consult the 8-K instructions, as that provides for immediate or earlier disclosure for that narrow set of material events.
It also allows companies discretion to use the 8-K disclosure for events of note that do not require immediate disclosure.
Some shareholders think every material event or event that an ordinary shareholder would want to know is subject to immediate disclosure, this is not the case, though bulletin boards love to advance this view. But it is also very possible that a company can choose to disclose events that happen that are not required but would seem worthwhile to make note of to the investment world as a very important development.
This is not to disagree with anyone, but to lay out the circumstances more clearly in order to have a more intelligent discussion.