Sometimes RMS is very literal and careful to use, or insist on, established definitions of words; however, the choice of “free/libre” was different, or skewed to only one perspective. It was a struggle for support, or marketing. A tactic. Almost propaganda. Who doesn’t like “free”, even if it causes confusion between free like beer, or like a bear in the wild.
Viral OSS, or Always OSS, or Copyleft OSS would be more accurate, but they wanted to emphasize “freedom” because it has a better image, and the others cause concerns.
I dislike proprietary software as much as anyone, but let’s be real about the tradeoffs and words.