9% of Americans say it's perfectly acceptable to hold such views.
Your subject line and your articles say two different things with you seemingly believing a false equivalence.
Believing that something is "acceptable" is not the same as BEING something.
Let me take an extreme example of this...
Being a pedophile, as horrible and atrocious as it is, should be acceptable. I find it utterly despicable, but in a free society that does not criminalize thought, the simple notion of being sexual attracted to minors should be acceptable. ENGAGING in pedophilia, however, would be unacceptable.
The fact that I think being one is "acceptable" doesn't mean I am on, doesn't mean I "support" it, doesn't mean I "approve" of it; it simply means that I don't believe it should not be "tolerated" within a society (and make no mistakes, if a society is allowing something to legally occur, it is "tolerating" it to some extent).
Holding white supremacists or Neo-Nazi's views IS acceptable, and should always remain acceptable, if we are a society that believes in the ideas of free speech, in freedom of political thought, in freedom of expression, in freedom of thought, and in the belief that one is only guilty under the law after they are proven to be guilty. To suggest such a thing does not mean the individual agrees with or likes such views, let alone IS a Nazi or White Supremacist.
The reality of polls like this an ambiguous nature of questions is the fact that it leaves it up to the responder to interpret what something like this means by "acceptable". Talking morally, ethically, legally, societally, etc? This is naturally going to give variations in how people respond, and explains why a larger % of people would likely answer "yes" than there actually are white supremacists/Nazis in this country.