Let me rephrase my observation. I haven't seen anybody from the right write a book and make the case publicly other than Roger Stone in the US. I believe that Charles de Gaulle was a conspiracist and he was more right of center than most of the modern European leaders and he was not what one would consider an anti democratic political figure. As to Jim Fetzer being a Holocaust denier does not automatically move a person's political stance to the right of center. There are plenty of Holocaust deniers who are left to far left of center. just to name a few there's old reliable Lewis Farrakhan, Linda Sarsour, Bobby Fischer and various Muslim leaders from across the globe. IMO, with the left now adopting a more pro-Palestinian and anti-Jewish/Zionist world view it's people from the left who are more prone to adopt pro Muslim attitudes and views while the opposite can be said to those from the right of the political spectrum. As to Michael Griffith just because a person adopts a pro-Confederate position does not make that position anti-democratic. Racist, yes. But if you would read the Confederate Constitution and followed the history of the Confederacy and the formation of it's government it was centered more on the rights of the individual states as having supremacy and against the controls that would be inherent in a federal government.
As I noted above, Jim Garrison was on the political right. He called himself a "conservative libertarian".
Another figure is Lew Rockwell, a libertarian/rightwinger. His site runs many of the pieces written by Fetzer and he himself (the last I recall) was a proponent of Stone's views that LBJ killed JFK. He's kind of an obscure figure.
And remember that the Liberty Lobby, a far right wing organization, published a piece claiming that E. Howard Hunt was one of the assassins (he was one of the "three tramps"). Hunt sued them for libel and Mark Lane, certainly no rightwinger, defended them.
We see popping up every now and then this very weird alliance between the far right and far left when it comes to the assassination. They disagree on nearly everything except, apparently, that JFK was killed by "the government", e.g., Hoover, LBJ, the CIA et al.