You're no investigative journalist if you claim that the holocaust did not happen and that the jews made it up.

Also: it's not a "theory". A theory is something you can research and come up with a result based upon evidence.

Therefore "conspiracy theory" is just just wrong. A "conspiracy myth" fits perfectly since it's a myth with a conspiracy in it's core.

So saying that some fascists spread "conspiracy myths" about the holocaust makes sense while it legitimises their bs saying that they spread "conspiracy theories".