Touchscreen pinching makes sense. It's undeniably intuitive, and pretty gratifying! And now it's everywhere—including places it shouldn't be, like the relatively tiny screen of the BlackBerry Bold Touch. This is like picking your nose with a mop.
The thing about pinching with your fingers is that it requires manipulating the screen with—your fingers. And the thing about small screens is that they're easily obscured beyond the point of usability by—your fingers. The BlackBerry 6.1 OS looks about as inoffensive as ever in terms of interface, but really, the pinch-to-zoom functionality looks shoehorned on here—shoehorned on with a shoehorn that's way too large for the shoe, and your feet.