Your friend is incorrect. Pixeljoint which is its members and not some entity does not look down upon non-limited palettes.
Most pixelart nerds with even minimal experience and skill do know and understand that limited palettes make for better technical pixelart and that limitations do not affect the artists' vision once this skill is developed and is the reason most like to focus on it. It is a most respected and valuable skills to master in the artform.
That said. Any pixelart you make is its own pixel and there is no such thing as a magic number of colors. The idea is to use the smallest possible shades you need and not a single shade over that.