Not so hard to understand...
Why not? The whole point of Anonymous is about hidden identity. It's one of those everyone and no-one things. If it makes it easier, think of it like a representative of the country, or a religion, or anything else.
- Group A supports or performs an action X, Group B opposes or disrupts the same action X.
- Group A and B identify themselves as members of Group C.
- Someone from Group C then says they are a representative of Group C and makes a statement about the intents, workings, philosophy etc. of Group C.
So what do you know about this person from Group C? They could be part of Group A, they could be part of Group B, they could be completely unrelated, they could be doing it for the lolz. They can have it none, both, and several other ways. All entirely intentional: designed to subvert the normal categorization of people as one group or another and in doing so making life very difficult for a lazy media and public that would have to think a lot less hard if they would call themselves A or B.
Anyone can represent Anonymous, but Anonymous is represented by no-one. It's a label, and about as useful as every other sweeping generalisation: Read statements about anonymous and replace it with something equally useless like: People >6ft tall. People who's skin is lighter than Cadbury's Dairy Milk. People who watch television. Suddenly it makes more sense: People who watch television are do/say/believe/support X. Other people who watch television don't do/say/believe/support X. Someone, who claims to represent people who watch television, says that people who watch television have no connection with X, and actually people who watch television do/say/believe/support Y. It's nonsense, but that's kind of the beauty of it - you can't pin it down, you can't label it, and no-one has an identity because they are (big or little a) anonymous.