Pedantic and wrong. What was your point here? Sign languages per your own link are expressed through manual articulation in combination with non-manual markers. That's gestures in common speech in all cases unless you are operating with the most specific and unhelpful definition of gestures.
Sign language is way more than just gesturing. I did not see read that link from the above post, regardless, gestures are fundamentally a semiotic expression of meaning with the body rather than speech.
Like sounds, one can create a basic Piercian sign, and build onto that sign.
I believe that sign language has the unfortunate implication of being composed exclusively of gesturing. The word “sign” is confusing as well, especially when “sign” signifies (pun intended) a set of commonly understood meanings in linguistics. Body language, gestures, manual expressions all are just parts that come together and become more than the total of sum parts.
I see spoken and sign languages as two different tools that can do similar job with different features and weaknesses. Like python vs go vs JavaScript.
Dictionary meaning of gesture.
> Sign languages (also known as signed languages) are languages that use the *visual-manual modality to convey meaning*
From the introduction to the wikipedia article.
Sign language is definitely made of gestures, at least by my understood definition of the word gesture.