But patent law is offensively fucked up. Basically, it's a war of money. Both sides line up patent lawyers (one of a very few formally recognized specializations for attorneys in the U.S.) and burn money until someone gives up. This case will almost certainly wind up before the Supreme Court eventually - unless Samsung folds and pays to make apple go away. Fortunately, Samsung is sufficiently profitable that it can saturate the process with more money than required and write it off as a margin cost for continuing to compete in the smartphone market.
Apple's patents are offensively bad. There *is* enough there to require a jury verdict to nullify them rather than a summary ruling by the Court (preferably one where the foreman doesn't lie about having a personal stake in proving that software patents are nearly always valid - like the last trial between these two) but in a sane system of patents there would be no question that "slide to unlock" is a variation of long established design concepts - i.e. a latch.