To me it comes down to a very simple concept.
Lets say a single mother of two has a very important force relic in her possesion that would greatly help both Jedi and Sith.
- A Jedi would negotiate and do something for the family that would help them in return for the artifact.
-A Sith would take the artifact by force, killing the family if they got in his(her) way.
So yeah, overall the Sith philosophy is 'evil'.