" I can't help thinking that; 'Our tactics are not reprehensible unless they're used against someone we like, then they are.' has a touch of two-facedness about it."
It really doesn't have any touch of two-facedness about it. It's natural to want the best for charities. There's loads of actions that are OK in one context and not too good in another. That's not two-facedness.
"Likewise deciding who gets to be anonymous, rather than who gets to be 'Anonymous', feels like crossing the line between being hacktivists and 'teh internet police'."
There's a tradition going back to the beginnings of Anonymous to out those they disagree with to the authorities.
"OK, so 'vereyone' is Anon, they have no 'leaders', the '99%', blahblahblah. So who set the rules if they don't have leaders? Face it, the whole Anon thing is just one big herding exercise, with the core Anons playing at building a zombie net made up of real people."
They set their own rules. You might not be able to understand it, but there's no hierarchy, no core, no formal votes, and so on. Anonymous members self-proclaim themselves as members, they know in a general sense what is expected of them and what is prohibited. It's not unprecedented. The LOD/H (Legion of Doom/ Legion of Hackers) in the late 1980s was real similar. LOD did have an actual leader when it started around 1985 (Lex Luthor of course), but he left to go to college. Since then, no leadership, no organization, no central authority, no organized membership. But, it rolled on until the early 1990s, when the feds decided to take down this "group" of hackers. They really couldn't wrap their head around it when they caught the first few people and they said no, they are not part of a cell; no, nobody appointed them to LOD/H; no, there's no leadership. Unlike now with Anonymous, back then once word got out the feds were looking for LOD/H members, there weren't any after that.