It looks like a tautology to me. Like: "Corruption erodes social trust in places where social trust exist and is key for the political system."
I think culture and education play much bigger roles than anything else, all the sources I find show Germany and France having similar level of corruption (on top of being geographically and economically close) but completely different level of "social trust". China's pretty corrupt politically but the social trust is quite high, the highest outside of northern europe as far as I can tell https://ourworldindata.org/c…
My company took the biggest telecom company in France to court for a violation of our license on a soft, license was GPLv2, we won, but it took 12 years.
Justice is a very poor and slow institution in France. For the same countries the budget of police forces per capita are nearly the same for example.