I was very specific in what I said.
There have been many acres of trees devoted to this debate in print. Some authors claim that ONLY freeze-thaw action can develop these polygons, and that therefore the existence of polygons is prima-facie evidence of thawing.
Other claim that thermal expansion can also develop polygons.
I presented a neutral statement that included both cases, and concluded with my personal opinion.
Mars will have the last word, whatever our opinions and preferences are...