Can someone explain to me the difference between American right and left?

[Undertoad]

To your examples,

Both parties support torture.

Both parties support the light torture of a small number of individuals who are threats to the USA. In general, voters and therefore both parties are against any sort of widespread torture, and the type of torture that they do support is a rather limited subset.

Both parties support violence against people who are different. Ruby Ridge is from Bush the elder, the Waco massacre is from Clinton, yes?

Yes; and both events are horrible, but both also represent a general failure of Federal law enforcement more than an enforced policy. Sometimes law enforcement is difficult -- and perfect law enforcement is impossible. We should work to be better than these cases, and I think the Federals have learned from them and have not repeated the problems that led to these events. In a country of 300 million people, we are not surprised that mistakes are made even though we are often appalled when they happen.

Both parties are keeping Guantanamo Bay open.

They certainly are. No mistakes here.

But all this also doesn't answer the original question, because we are talking about Democrats and Republicans which are not really the same schools of thought as lefties and righties.