Has he posted anything here for which he should be banned?
Only in that he's demonstrated terminal stupidity on the order of Flat Earthers. Without his racist trash I would place him on the level of a tesla, except that he likes to bring childish insults into the mix as well.
I think he will not be able to follow the forum guidelines (even with the wide latitude he is getting now) and will deserve a ban before very long in any case.
I simply don't think evcforum wants to provide posting space for the type of violence-inciting racist feces that frequent Stormfront. Others have copied some of SO's actual racist diatribes, including assertions that blacks are incapable of forming a civilized culture, support for eugenics, etc. The same username was (as I linked above) posting the same sort of pseudoscience that our SO was - I think it's clear they're the same person.
You guys run the place, so the decision is up to you obviously. But I for one am not going to respond to any post of SO's. I see no reason to dirty myself through correspondence with racist garbage.