According to
Road to Laugh Tale (Vol. 2), meitos can actually be polearms, claws, axes or even blunt weapons, like Kaido's club or Kanjuro's brush (yeah, they're meitos, but have no grade). Katakuri's Mogura ("Mole" in the page below), for example, is a ranked meito, but with a still unknown grade. Killer's Punishers are there too.
Considering that, I don't think that Whitebeard can be regarded as a swordsman. If you do consider him a swordsman because he had a meito, then you should consider Kaido and Katakuri swordsmen too.