The question of the face veil is a real disagreement within Islamic jurisprudence, not a difference between the devout and the lax, and it turns on a specific textual point.
Quran 24:31 instructs believing women to guard their modesty and not display their adornment "except what ordinarily appears of it". What that exception covers is the whole argument.
- Most classical scholars, including the bulk of the Hanafi, Maliki and Shafi'i traditions, read the exception as the face and the hands. On that reading covering the face is not obligatory, though it may be meritorious or advisable in particular circumstances.
- The Hanbali school and much of contemporary Salafi scholarship read the exception more narrowly and hold face covering obligatory.
- A substantial body of modern scholarship, including at al-Azhar, states plainly that the niqab is a custom rather than a requirement, a position that has itself been politically contested.
None of these are fringe. The disagreement is ancient, it is argued on shared premises from shared texts, and it has not been resolved.
What the law does with it is a separate matter, and the legal argument about face covering differs from the argument about headscarves in a way that is frequently glossed over. A covered face engages claims about identification, about security, and about the conditions of interaction in a shared public space that a headscarf simply does not raise. That distinction is what the European Court of Human Rights accepted in S.A.S. v. France, resting the decision on living together rather than on security, having found the security argument insufficient on its own. The UN Human Rights Committee, considering equivalent French law in 2018, held that the same reasoning did not justify a criminal penalty on a small number of women.
Both bodies were reading the same facts. They weighed them differently, and neither result binds the other.