I think it is because some article headlines are worded in such a way that these (so far two revealed) local Captain Americas are touted as being on the same level as Steve Rogers, Bucky Barnes, or the others. However, neither of the two marvel.com articles explicitly says that each names himself or herself "Captain America" in-universe, so we don't know if in-story they will actually call themselves as "Captain America" by itself; "Captain America" with another word added; or something else altogether, even as their costumes are all too obviously derived from Rogers' or Barnes'. Joe Gomez is called the "Captain America of the Kickapoo Tribe" in the US of CA #3 article, and Alyssa Wong does call Ari Agbayani as a "new, local Captain America" in the US of CA #4 article, but those are for promotional purposes.

And, there are different tiers or levels of "hero" or "superhero". It would be in-character for Rogers to proclaim Joe Gomez and Ari Agbayani as local heroes in their own right for their own communities.