Is it permissible to be absent from congregational prayer due to the imams' incompetence and the authorities' harassment of worshippers who adhere to the Islamic dress code?

Congregational prayer is obligatory for adult men. It is not mandatory to perform it in the mosque; it is valid in any location. If you are unable to pray in congregation outside the mosque and fear a definite harm to your body or livelihood, then you have a dispensation to omit the congregational prayer. However, if the fear is imaginary, there is no dispensation.

Do not be lenient regarding the matter of congregational prayer. Advise imams who commit some sins with gentleness and kindness, and teach those who are negligent in learning. Prayer is valid behind any Muslim who performs prayer well and does not violate any of its conditions, pillars, or obligations, even if he is a dissolute person. If the imam makes an obvious grammatical error in Al-Fatiha that changes its meaning, then prayer behind him is not valid. However, an error that does not change the meaning, or an unintentional error in parts other than Al-Fatiha, does not invalidate the prayer.