The article is yet another unsubstantiated piece by the author (will not mention his name here), in line with other extremist and poorly sourced clickbait pieces like this one:

‘A nightmare scenario’: how an anti-trans Instagram post led to violence in the streets'

The documents released by the Brennan Center simply do not support the claims of the news article. This fits a pattern of the author citing anonymous sources and then public sources which do not back up his story. It's unfortunate how low the Guardian's standards have fallen that they would allow this mishmash of agit-prop on their newspages.