Treason never prospers.
If one is charitable, one can say that the support for Sen in the "movement" is due to ignorance: some folks just didn't know Sen's full range of opinions, were not aware of the good and great Giacomo Vallone, just didn't know that Sen is an anti-WN "culturalist."
If so, then that of course doesn't reflect well on those supporters, who failed to do due diligence in studying Sen and his beliefs before endorsing him. That failure is compounded by the fact that Sen hasn't been shy about his views, openly declaring opposition to White nationalism in various forums, promoting civic nationalist culturalism, and, of course, openly admitting his non-White ancestry.
Well, the ignorance is over; the facts are known. To still support Sen is nothing less than race treason.