If Dumbledore did block Harry's fanmail, it really doesn't seem all that manipulative. It just seems like a good idea, considering that he both

A. Lived with Muggles, in a Muggle populated area that might think it was strange that so many owls were flocking to Number. 4 in daytime

B. Said Muggles didn't like him, and didn't take kindly to the few owls Harry did recieve from friends and the like.

And C. Before he joined the wizarding world: at ages 1-6 he couldn't even read, and at ages 6-10 he didn't know about the wizarding world.

In fact, if I had to hazard a guess, I'd say Dumbledore did inform Harry he was blocking his fabmail sometime during first year, and Harry was just fine with that. It just wasn't important enough for us to see on-screen. Like the bathrooms at Hogwarts- there aren't really any described in the dorms, and there aren't any described out of them until they are important for plot purposes, but that doesn't mean that wizards don't pee.

This whole manipulative!Dumbledore seems to be a bit exagerated, imo. Some of the things people go ZOMG MANIPULATIVE at kind of make sense if you think about them. I don't know about you, but I was in no way shape or form equipped to handle the knowledge that my destiny was Kill-or-be-Killed when I was eleven. Dumbledore probably should have told Harry about the prophecy sometime during fifth year, but if he had told him when he just entered the wizarding world, Harry probably would have just freaked out and got the hell out of Dodge.

 

Book 7 pretty much destroyed any possibility of redeeming Dumbledore. There's no way out of it: either he's grossly incompetent for allowing the sole hope of the wizarding world to be exposed to danger time and time again, or he's a manipulative bastard for crafting those scenarios to prepare Harry.

As for the fanmail thing, I'd guess someone (likely Dumbledore) blocked his mail from an early age because of the Dursley factor (and because he's too damn young to read it anyway), and then simply forgot to remove it later. Anyway, even if canon Harry heard about it, do you really think he'd be jumping at the chance to be swamped by attention?

/beating dead horse