Piety is not established by announcing oneself righteous. Truthfulness, fulfilling obligations, avoiding harm, and correcting mistakes are among its visible demands. Despising others on account of lineage or colour contradicts the lesson itself.
If someone boasts that their community is inherently superior, the appropriate response is that spiritual worth is not decided by ancestry, while maintaining respectful speech toward everyone.
In بِتَقْوَى, the preposition bāʾ indicates the basis or cause: the exceptional superiority is linked to piety, not to complexion.