You're being downvoted, but you're correct. Values espoused by the founding documents of the current United States government are also properly called American, even if the majority of americans disagree. There's two possible meanings here that is causing people confusion.

One might argue that technically (akshually?) the Bill of Rights goes against the founding documents of USA, amending them a few years later with values that were not in the original constitution to satisfy anti-federalists criticising the initial design (and its values).

So you're saying that slavery is an American value?

It is, after all, in the Constitution, although its popularity has waned of late.