Why ObservableCollection does not have a RemoveAll method?

Why ObservableCollection doesn't has the RemoveAll method like a List?

I have implemented an extension method to provide this functionality to the ObservableCollection, but I would like to understand if there is a specific reason for not providing this functionality.

Would it possibly effect Data Binding in some way due to Collection change? This post does specify a few things that could go wrong while using ObservableCollections, but does not address this question.