It doesn’t matter where your political affiliation lies. It doesn’t matter what your stance on gun control is: you cannot support the No Buy list. The essence of the proposal is simple: the government declares a person a “bad guy” with no trial and no evidence, and that person loses their inalienable Constitutionally-protected rights. Regardless of your opinion of the Second Amendment, the Bill of Rights is meant to act as a bulwark against tyranny and dictatorship. If the government is able to bypass this bulwark by simply declaring it has the authority to do so, the United States is a literal dictatorship.
The government has an established pattern of overreach and abuse. If this is allowed to stand, government officials will have established legal precedent to rescind any other right you hold dear by simply adding your name to a list. Don’t even consider what this proposal is trying to do, look at how it will do it. There is no due process, which is the backbone of free society. The government simply declares you an enemy of the state and removes your rights.