You probably have three important questions on your mind right now:
|•||Why are the bindings so difficult and so nonintuitive?|
|•||Is there any chance that I will ever learn all these strange bindings?|
|•||Can I change the binding so that undo is bound to Ctrl+backspace, for example?|
The short answers are “Don’t you have more important things to worry about?,” “Yes,” and “Yes.”
The more detailed answers follow.
To the question of whether you will ever learn all these different bindings, yes, you will. It will come with time, if you just force yourself not to use the mouse when alternatives are available.
The reason for the bindings is not very clear, but a good guess might be that it is because Emacs was not designed from scratch, but rather ...