1) Clarity as immediate intelligibility is based on the ideal of linguistic transparence.
2) Transparence is based on familiarity (of words, grammar, objects and relations): a doxa.
3) Philosophy is singularity breaking with familiarity, using words in unfamiliar ways: unfamiliar technical terms, conceptual grammar, ontology.
4) Philosophy, like science, explains the familiar known in terms of the incommensurable unknown.
5) All these concepts are temporal, not static essences: that which is unfamiliar and unknown, we can make familiar or known.
6) Democracy is not static uncomprehending tolerance, but doing what it takes to relate to the unknown other.
For an application to Foucault’s supposed obscurity see here.