First of all, a qualifying statement.
We're all for the metaphor of not growing up, of holding onto wide-eyed childlike innocence, with some of the finest examples of art across a myriad of media having dealt with the search for wonder in an adult life of jaded cynicism, lamenting the loss of innocence and the purity of childhood joy. Pieces like Peter Pan, Never Let Me Go, Forrest Gump, Toy Story, Lord of the Flies...these are all examples of art that deals with the loss of innocence. The most successful, the most worthy, often deal with that loss and set about finding a way of recapturing it, with the conflicts and complications of adult life thrown in to provide some obstacles on the way there. Should the piece be a comedy, in the broadest sense of the phrase, a happy ending more often than not sees a reaffirmation of the importance of having a youthful heart at the very least.
When Robin Williams rediscovers that he can fly in Hook, for example, we cheer and smile. Here is another middle aged man, dressed all in green, frolicking about in forests with fairies. But we accept it. The Boy Who Never Grew Up has grown up and been lost, but his return heralds a change of heart in him, and sets the ending up for (SPOILERS) a reassessment of his relationship with his family. Peter Pan's return to Neverland reawakens the child within, a change that he takes back with him to his 'real' life acknowledging that he now has the responsibilities of an adult, but assuaged by the new knowledge that one can still be, indeed one still should be, young at heart.
This is not something we get from observing a rotund, middle-aged mercenary creeping about the place, pretending to be a fairy, selling directions to kids.
Peter Pan and Neverland are bound together - the world and the person belong - but Tingle is weird even by Hylian standards. Aside from being one step away from getting his name on a list and a profile on a prison register, Tingle is an extortionist and sits merrily at the top of his tower (in Wind Waker) while his two two slaves (yes...SLAVES) crank the tower round and round so the little fat imp can enjoy the pretty vistas. Plus, just look at that nose...you just know he's a raging alcoholic, and a drug-addled fiend to boot. It would explain a lot.
If you went wondering in the forest, saw a small, fat man bellowing nonsense, grabbing at fireflies and trying to flog children expensive maps, you'd ask him what the hell he was doing before calling the authorities. And that's fine. PedoBear has nothing on Tingle.
Perhaps the worst thing about Tingle is that we are completely unable to affect him. No matter how irritating he gets, no matter how many times he shouts ''KOOLOO-LIMPAH!', we're unable to clock him over the head with our sword or cheekily place a bomb in his pocket. Everyone who ever played Goldeneye surely felt a small twinge of satisfaction the first time they bumped-off Natalya themselves. It was therapeutic...after all, she'd only have gotten herself killed anyway! But no, along with Slippy Toad (and often Zelda's own Navi), Tingle remains an irritant you simply can't remove, more's the pity. Nintendo might as well have just called him 'Jar-Jar' and had done with it.
We can understand why some people warm to Tingle, the things he supposedly stands for are genuinely appreciable and positive. But we don't find him funny, nor do we find him endearing. And frankly his use as comic relief would be far more effective if the developers had him being pelted by rocks. Or chickens.