Progressives BELIEVE that White Conservatives are racist.
The problem with this belief, is that White Conservatives KNOW that it isn't true, because they are said White Conservative.
This puts Progressives in the same position as a Flat-Earther, BELIEVING in something that most people KNOW is not true.
Most often, a person's BELIEF system sticks to things that are not provable, like whether there is a Supreme Being/Creator of the Human Race, or not. Nobody knows if there is one, so we are left to believe what we choose.
However, many Progressives are unchurched, and have replaced religious beliefs with political ones.
The problem is that many of their Political BELIEFS are based on their own fears/biases, and can be disproven by people who KNOW different. A person KNOWS whether they are a racist/sexist/bigot or not. Your BELIEF that they are does not change the truth, which only they know.
So there you have it, the Simple Reason that White Conservatives will always win the #racism debate, because Progressives can only BELIEVE they are, but they can't know the truth. Only the White Conservative can know the truth, and most of them KNOW that they are not racist.