1. Domestic terrorist organization specifically is not a thing under US law, that is true. But domestic terrorism is, and we do have RICO statutes. (https://www.congress.gov/crs-product/R47885)

2. Not incoherent. Seems pretty specific: All relevant executive departments and agencies shall utilize all applicable authorities to investigate, disrupt, and dismantle any and all illegal operations — especially those involving terrorist actions — conducted by Antifa or any person claiming to act on behalf of Antifa, or for which Antifa or any person claiming to act on behalf of Antifa provided material support, including necessary investigatory and prosecutorial actions against those who fund such operations.

I think you've triggered them