Pseudo-history, and related issues

[Tiberius Clodius Corvinus]

It is not pseudo-science or pseudo-history, because authors like these are pretty serious.

Why not? I think you're to nice. Dedication and dilligence are no scientific criteria in the closer meaning. Never been and never will. There's reasons why the scientific community developed methods and standards over centuries for what is correct (or rather acceptable) methodology and what not. If one doesn't stick to the rules - be it unknowingly or not - and appears to be using scientific methodology when in fact he's not, it's perfectly appropriate to call it pseudo-science. Because it is. There's no need to be PC about.

Maybe 'popular history' is the most recognisable.

Hm, I don't know, here we use that term basically for kind of a shortened version of "real" science, in order to make complicated ideas more understandable to a wider audience. While the term is of course slightly derogatory IMO, it doesn't automatically imply the scientist in question doesn't work properly or his results or logics are flawed.