I imagine without modern frame hives and honey extraction equipment, the honey had a lot more crud and contaminants in it.
there is a lot to be said for using raw honey with all the crud and gunk in place. a lot of that stuff (wax, propolis, pollen, bee bits etc) add nutrients that the yeast need. course you could use yeast nutrient but to my mind if I can get it from the 'honey' mores the better. course I am something of a caveman brewer when it comes to mead.
The best braggot I ever made (won a gold at NHC way back when) used crystallized farm-fresh honey that had bits of comb and other stuff in it. I also boiled the must, not knowing any better, and skimmed the scum. I used Cal Lager yeast with no nutrients.
It may have been beginner's luck, but it won a lot of competitions. 'Amazing what can happen if you don't know the rules.