Why did the grench hate Christmas?

Answer 1

It is never explained as the point of the story is how Christmas is more than just presents. As the audience is children it is assumed that they will just get the message and not ask awkward questions (which they always do). You could make a prequel which explains it if you have enough time on your hands to ask questions like this*.







*Don't point out I must have enough free time to answer questions like this.