The Continuous Esteem of the Prophet's Family is perhaps the greatest work about the Family of the Prophetic Offspring (Ahl al-Bayt). The renowned scholar and prolific author Shaykh Yusuf al-Nabahani, has written a text which is unparalled on this subject.
The main opposition against the Ahl al-Bayt are unrighteous people who are in positions of power and influence. They feel their positions to be under threat so remove the Ahl al-Bayt from their places of work or even fight them.
This is essentially the struggle Imam al-Husayn, may Allah be pleased with him, faced against corrupt leadership. This opposition continues to exist to this day as people who are trying to do good are often marginalised and those who are doing evil are brought to the fore.