1. The tragedy that befell Imam al-Hussein, and we call it "the great tragedy" in Ziarat e Ashura, was not getting killed and beheaded or the capturing of his household, rather, it was the tragedy of the rejection of (infallible) Imam from the position that God had chosen for him.
2. We read in Ziarat e Ashura: "so, I beseech Allah Who has honored your position and honored me because of you, to endow me with the chance to avenge you with a (Divinely) supported leader from the Household of Muhammad s."; which in short means that I want to take your revenge with Imam al-Mahdi.
3. If Imam al-Hussein (peace be upon him) questions us, "What is my revenge?" What will our answer be?
4. Most mourners would say: "they cut off your head, insulted you, cut off your finger, denied your access to water and killed you while you were thirsty, killed your children and captured your family..."
5. These are not the tragedies of Imam al-Hussein (PBUH) because there are numerous cases of such crimes throughout history. For example, one of the crimes recorded against a prophet was cutting him in half with an ax (the prophet Zakariya) and Qur'an says: "إن الذين يكفرون بيات الله واقتلون النبيين" Those who deny Allah’s signs and kill the prophets" (3:21).
6. Also, if the tragedy mentioned in Ziarat e Ashura was referring to this kind of crimes, then one might say "There were many people who were in a worse situation than Imam al-Hussein (a.s). For example, our soldiers in Kurdistan were beheaded using the most heinous methods, and they were scalped using the coarse side of mosaic tiles and with tinplate."
7. If "taking revenge" was referring to these crimes, then Mukhtar had already avenged them completely.
8. So, why do we cite in Ziarat e Ashura that his revenge is not taken and we want to avenge him with Imam al-Mahdi?
What does it mean when we say "seek revenge for your blood" in Ziarat e Ashura?
What is "your blood?"
Or what does it mean when we say "Peace be upon you, oh blood of Allah"
Imam al-Hussain is the blood of Allah.
It means that he is the source of spiritual and human life.
When people are deprived of an infallible to guide them, they are deprived of a spiritual and human life. So, fulfilling the requirements of a human life becomes very difficult for them.