No, I don't think you owe an apology. It's a super common terminology almost to the point where I wouldn't really even consider it outright wrong to describe it as a SoC. It's just that the blurred distinction between a single chip and multiple chiplets packaged together are almost impossible for an outsider to tell without really getting into the published spec sheets for a product (and sometimes may not even be known then).

It's just more technically precise to describe them as SiP, even if SoC functionally means something quite similar (and the language may evolve to the point where the terms are interchangeable in practice).