What is the ruling on someone who lets his garment hang low leading the prayer, and what is the ruling on refusing to pray behind him as a form of objection to him?

The imamate of a person who lets his garment hang below the ankles (musbil) is valid. Whoever abandons congregational prayer for this reason has erred, for the imām's isbāl (letting garments hang below the ankles) is not an excuse that permits leaving the mosque after the adhān and missing the congregation. And leaving the mosque after the adhān without a valid excuse is not permissible. Ibn Qudāmah said: "It is not permissible to leave the mosque after the adhān except for an excuse." It was narrated from Abu Hurayrah (may Allah be pleased with him) that a man left after the adhān, and he said: "As for this one, he has disobeyed Abū al-Qāsim (the Prophet), may Allah's peace and blessings be upon him." It was narrated from Uthmān ibn Affān (may Allah be pleased with him) that the Messenger of Allah (may Allah's peace and blessings be upon him) said: "{Whoever is overtaken by the adhān in the mosque, then leaves, not for a need, and he does not intend to return, then he is a hypocrite}."