I think both of you are talking about the same thing.
Please don't assume that your views are generally held or will meet with general approval. I think what you're saying is completely wrong and wildly inappropriate. In general, there will exist many terminal applications where the designers should feel absolutely free to use 256 and full-RGB colors if they wish to, seeing as the technology has supported it for years.
An example is color themes for syntax highlighting; the designers of color themes obviously _can_ restrict themselves to 16-color palettes (e.g. https://github.com/chriskempson/base16) but they are perfectly free not to. I do not understand what makes you think you have the right to demand that people impose such a vast restriction on terminal applications. The web supports 256 colors and full RGB; why shouldn't terminal applications?