Why is truth the fundament and preceeds principles like freedom, nationalism, etc. Because it is scientifically proven that cooperative i.e. true behaviour is the key to higher order organisation forms and organisms. E.g. https://en.wikipedia.org/wiki/Tit_for_tat and the more recent "generous tit for tat" approaches.
We extend the principle of truth to those of respect and peace, because thruth alone can be very harsh and unforgiving. But the motivation to propose respect and peace as fundamental laws that give meaning to the decisions we make as individuals, companies, communities, states and the entire humanity is the same as for truth: it is the proven concept that allows us to survive.
Therefore, truth is not a religion as defined e.g. by https://en.wikipedia.org/wiki/Yuval_Noah_Harari.