That just seems unrealistic and rather extreme. Like a statistic from CNN. I'm not saying that racial biases doesn't exist, but claiming that at least 30% of people are racist is pretty much saying that for every three people, one of them is a black panther or klan member. I don't know anyone associated with either organization and I know more than three people.
You don't have to belong to the named organizations (or similar) to have a latently racist orientation. Remember the quiet "outrage" when Obama was elected? At a time when the USA was becoming somewhat proud of its lack of "color bias", it seemed.
In general, I'd suggest that the percentage can vary with location, financial demographics, etc., but I tend to agree that the claimed 30% is probably, in total of all levels of racism, conservative.
Respectively,
CBODY67