What if you find out that the other other person supports strong enforcement of existing immigration laws? What if supporters of that policy are being labeled as a "white nationalists" by others? Is that really evidence of "white nationalism"? What if that person simultaneously supports significant changes to the immigration laws that would result in more legal immigration?
If the answer is no, I would kick them out just the same and that's ok.
People who are actively sharing white supremacist screed are not nearly in the same category.
Ex-cons have a shitty past. White supremacists are currently and actively shitty.