Linguistically, Ahl al-Qibla means people who turn toward the qibla. In its religious use, it denotes Muslims who accept the teachings brought by the Prophet ﷺ and believe his reports.
Outward prayer and inward belief are connected but not identical. Simply facing the qibla does not establish the whole creed, and an outward failing does not by itself negate every element of a Muslim's faith. Profession and affirmation remain central.