Is "Christians" here just a dogwhistle for "white and far-right"?
It means people who self identify as Christians formed a fundraising service specifically for social media fundraising that won't be accepted by other services because of alleged religious bigotry. This group of self identified Christians has now raised hundreds of thousands of dollars for the legal defense of a brainwashed teenager turned domestic terrorist. Is someone going to say that they aren't Christians because they are giving aid and comfort to domestic terrorists? Who gets to decide who is or isn't a Christian? Certainly not me. I believe them when they speak. I believe them when they talk about racial superiority and the violence they feel free to visit on protesters.
Sort of. The word "Christian" has a few meanings here in the States. There is a subset of people, the people who raised or dear OB, who think that it means, roughly, "one who rejects modernity, believes the Earth is 6,000 years old, and hellfire and damnation are nigh." These people make up the majority of white nationalists.