As far as I can see, the force is an innately evil force, or all sentient life capable of tapping into it is innately evil. If the default end of a force sensitive person not avoiding their natural passions is to end up as a psychotic killer, then the force is pretty **** evil. The Jedi say that we have to avoid love, fear, anger, ambition, curiosity and everything else that defines humans and become a blank slate of calmness. They say that if we don't we will fall into the dark side and end up evil. They say we cannot love our own mother or fear for her safety without the force dragging us to evil.
The force presents a constant battle between neutral and evil, where the default setting is evil winning inside an individual. Good does not really enter into the picture. Any goodness shown by the Jedi is a calm pragmatism, or a leftover passion for justice or compassion that they have not managed to purge yet. Up until the last movie, we never heard of the good side seducing anybody and being addictive, no, the force has only every dragged people to evil. People that were good, were good despite the force, not because of it.
As such, I agree with the earlier posters about the force not changing its nature due to the ideology of its user, it will remain as is. As for the OPs question, can somebody think that both ideologies are bogus and just do whatever they want with the force? Sure, we call them Sith. We call them despots, tyrants, psychopaths and worse. Without the discipline of the Jedi, the dark side is too strong and seductive, giving into your passions and desires can only end one way.
Personally, I think that the Force, like any other energy, is neutral, and the good or evil in anything done with it comes from the outcome of and intent behind the actions, not from whether the Force was used to do it.
The Jedi and the Sith and every other tradition that attaches deep moral significance to the Force itself is projecting their own beliefs... they're getting out of the Force what they bring to it.
Edited by MaxKilljoy