This is so true! Ok, not all historians can be categorized this way, but some certainly can. Like, for example, Mike Silver, whose anti-modern bias is beyond cringeworthy. He's hands down the worst example, I can think of!
Concerning Silver... my personal opinion is, that boxing had reached its "modern" form by the late 30s/early 40s, and that no significant improvement/evolvement has taken place since then. On the other hand, I can't see a significant DEvolvement either. I think there are fine fighters today - just like there were 80 or so years ago. But if Mr. Silver believes boxing isn't what it used to be, that's fine. He's certainly entitled to that opinion. However, many of the interviewees in his book expressed opinions so outlandishly crazy, that I don't understand why a respected historian would lend his name to such drivel.
I like researching this stuff, but I make a point not to call myself a boxing historian, because I'm cerainly not qualified to be a historian. There's a serious lack of proper historical method in boxing history and it shows.
If we define a historian, as someone with a deep interest and insight in not just what boxing is today, but also what it used to be in the distant past... then you're being too modest!
For one to frequent their local tavern and sit in the corner playing dominoes amidst a smokey haze from their cuban cigar, with 1920's newspaper clippings to their right and a Jackie Blackburn biography to their left. Always refer to the barmaid as "darling" and order only half whiskey's.
I'd say many that are thought to be Historian today, are more just researchers, and like anything some more informed than others... Historian are researchers too, have susbstancial resourse material and have put years & years into it. But Historians can be broken down to different types so to speak... Historian 'General' know lots of bits & bites over the course of Boxing History. other Historians will have a more Specific Lean, i.e Era's or Divisions (Pollack's HW Books), or Modern or Bare Knuckle Era and so on. But at the End of the Day, "the Resources have to be sourced in order to Complete a Thesis. there are Dozens of SERIOUS Collectors Worldwide, who though not neccessarily Historians, can resource Era's, Fighters, Weight division or Title linages for example and help Historians and or Serious Fans confirm things that they might not be able to access otherwise. So 'Historian' can be a loose definition, which might be more attributed to Serious Researcher. But like someone said earlier the ones that don't tout themselves as one are often more accurately Historians.
People who have studied and know everything about a subject are experts. Historians, like scientists, produce new knowledge or sythesize existing knowledge to answer new questions. The key here is to first become an expert, watch the fights, read some books, etc. Then once you've identified something unknown that's worth knowing, you embark on research using the methods of a historian. Primary sources, secondary sources, oral tradition (particularly rich in boxing though it's disappearing fast), interviews, whatever makes sense. https://libguides.usc.edu/humanitiesresearch/historical