That's actually complete bullshit which mainstream left media pushed and hammered around as usual.
I've done some reading into this and there's several leaps to conclusions made as part of this story.
Firstly, we don't know that Palmer had any knowledge of the activities of this group other than "meme magic" and general internet trollery and sillyness, a far far fucking cry from genuine Nazi / racist posts that the group is accused of.
Secondly, upon doing some reading, I can't find any evidence that this group did anything than produce one single lame billboard which simply said "too big to jail".
Seriously, I had real difficulty finding actual evidence of what they produced, infact on my search all I found was a couple of posts by people saying exactly the same thing "What did these people actually do?" and thus far, no one can provide anything but one lame billboard.
It's entirely possible infact that Palmer was actually simply ripped off by Nimble America and the only way they stopped him litigating / calling them out is doing the billboard.
While Palmer said some dumb trolly stuff, considering his age and reflecting on myself, I've said dumb, hyperboilic trolly shit online over the years when younger too.
I suspect he did lie about being a Gary Johnson voter and he did infact vote Trump.
I suspect he owned the Reddit account he was accused of owning, which said some lame and stupid things if I recall about democracy.
All said and done though, what he does with his PERSONAL money in his own time is none of my business, it was kinda dumb and handled poorly but until someone can actually provide for me irrefutable evidence that he ACTUALLY KNEW that this was a "Neo Nazi" group AND some evidence of their "Neo Nazi" postings and work, then I don't know what to say, just people leaping to conclusions because "I hate Trump, all righties are Nazis!"
(Note: Not an American, I have nothing in this game, except I am sick to high heavens of misrepresentations of the truth in media, be it omitting details, exaggerating details, clickbait headlines, leaps to conclusions and other such things.)
Note 2: If you can and will provide evidence that Nimble America really genuinely produced nasty shit, I'll gladly apologise, however I still may not be convinced Palmer was actively aware of this and pushing it. Possible but nothing anyone can ever know for certain.