These are propagated by those who hate to see the remembrance of Ahlul-Bayt...

These are propagated by those who hate to see the remembrance of Ahlul-Bayt, and they resort to all possible means to mock to Followers of the Members of the House of the Prophet (PBUH&HF). And you has become their voice unwittingly, I presume. Usually the ceremony includes speech by a learned man with regard to the movement of Imam Husain and his aims and his message.

Then the speech continues to reminding the heart-breaking events of the catastrophe of Ashura and those who have human heart will cry, and mourn. Of course, there are traditions transmitted by Ahlul-Bayt which state, crying for Imam Husain, or making others to cry for him (through speech and reminding the events) has a lot of rewards. In fact, all the prophets of God without any exception cried for Imam Husain and commemorated Ashura, including (PBUH&HF).

Not only that, but also the Jinns (unseen creatures) mourn for Imam Husain. I have mentioned some of traditions affirming this fact in my previous posts quoting from Sunni collections. Nonetheless, we affirm that hurting own body is forbidden. Some people may get very emotional and do that, yet the rest are not to be blamed. An analogy is the case when a person loses a dear one, where s/he will cry for him.

Due to the height of emotion one (specially women) may start beating herself to the extent that it causes harm for her body. This is what is forbidden, while what has no harm to body (including beating chest) is allowed. Thus the commemoration can not be questioned by the innocent overreaction of certain individual(s).

The explanation that I was given (by Non-Shia's mind you), that Shia hit themselves as a punishemnt that they left Imam Hussein go from Koufah (?) alone with a few men and did not help him. At the same time it was them who sent for him to come and lead them to fight for his right to be the Khalifah. It is really amazing that you readily accept such rumor without even giving it a second thought.

Even I suppose the Shia killed Imam Husain in year 61 AH, why should I feel guilty about what some people did in the history? Even suppose my father killed Imam Husain, then why should I feel guilty of what my father did? The sin of a sinner will never be inherited to his offspring. (The ancestors may have a share of such sin if they mislead their offspring, but the reverse is never true).