Why is Fan Wank called Fan Wank? It makes this British troper giggle inappropriately every time the topic is brought up. (And makes discussions like the one above rather more disturbing...)
Because its an activity which is basically harmless, not considered morally suspect by rational people but does not really add anything constructive to the world except a bit of pleasure to the participant. And if you do it too much, you go blind.
Also your friends tend to abandon you if you do it around them, especially in public.
As this troper understands it (correct me if I'm wrong here, but I've seen Americans use it this way before) wank seems to be the US equivalent of whinging or slang for something incredibly stupid, and because the majority of native English speakers - both on the net and in the world - are in North America it's more likely that non-native English speakers will see that usage of wank on the net. It's much easier to catch onto that meaning of wank, since it's more common to complain about someone else... well complaining or being stupid, than to be talking about ahem... ADateWithRosiePalms. So it's usage for a trope would seem practically harmless to a lot of people who use the net regularly. Too bad for those of us who use wank to mean something else, it's one of those phrases we need to keep out of polite conversation.
I live in America, and I've never heard the term "wank" used to mean anything else. Of courseFan Wank is a reference to A Date with Rosie Palms. Masturbation is meaningless self-gratification. So is making up a convoluted theory to "excuse" a canonical detail or development you didn't like and posting endlessly about it on the internet.
A quick and dirty explanation of what the word means in all non-A Date with Rosie Palms examples: A excessive, solitary activity that benefits only the wanker is and unpleasant to anyone else.
And in conclusion, "fan masturbation" took too long to type every time.