Just two cents from an old Sith here, don't mind me...
Some Force powers are designed as weapons, and in that sense, they're of a Darker persuasion. However, an excellent point made is that many of those can be used toward other ends. Obliterate can clear rubble, to restate one example. Even so, some powers are unquestionably Dark Side powers, examples being Choke, Crush, Sever Force, and Dominate Mind.
Choke has one purpose, strangulation. Few and far between are the instances in which it is alright to strangle someone. Crush is more of a direct example; if you have someone in a position to fold their body up like a napkin, why didn't you simply subdue them and take them hostage?
Sever Force has only one acceptable "Light" usage, which is to stop Sith Lords and other Dark Side adherents from using their abilities in harmful ways. Even so, many will argue that redemption is possible, and that there are better ways to stop them. I'd liken its usage in many cases to rape, simply because you're forcefully taking something sacred from them. Thus, without supreme justification, it's a Dark power.
Finally, and this is my strongest suit; Dominate Mind. This power makes the user your absolute puppet, walking your walk, talking your talk, doing whatever you please. You completely override their thought processes and replace their will and feelings with that of your own design. It's so powerful an act of control that its victims are usually left debilitated and handicap. How, in any way, is it not Dark to completely destroy a person's mind in the name of controlling them for a certain period of time?
Quoting the knife example, another good example of most Force powers would be the hammer. It makes a very effective weapon by all means, but it can also be used to make things and to fix things, or to clear away obstacles. A knife can cut and stab, but can also be used for cutting food, among many other purposes. The Dark Side powers I've listed, and others, are akin to swords; too long, too thin, too light, and improperly shaped to be a tool. They have one purpose; to kill.
Seems I really know how to stretch two cents...