“Built on a standard Model 700 action...” kind of sounds like a bolt-action rifle to me, unless the bolt is welded closed or something. Oh well, I pretty much don’t know anything about modern muzzle loaders, or what they consider muzzle loaders now. I think as long as you have to put any part of the charge in from the muzzle, you can call it muzzle loading.
In any case, the writing displayed in the article is embarrassingly bad. I’d be curious to know what makes Jim Shockey “infamous”, though.
Several of the "inline" designs have bolt and striker assemblies that close over the primed breech face of the barrel - the Remington is unique in that they reamed a deeper primer pocket and made it work with a primed case instead of fumbling with loose primers. There's a solid partition between the "chamber" and the rear of the barrel, with only a flash hole drilled through so the primer flame can reach the powder charge.