What is the Sunnis' attitude in regard to the revolution of Imam Husayn(a.s.)?

Every body recognizes the high rank of Imam Husayn (a.s.).His grandfather is the Holy Prophet (s.a.w.). The Holy Prophet (s.a.w.)was always describing Imam Husayn (a.s.), that he is the counter-balance of the Holy Quran. And in other tradition he (s.a.w.) declared that Husayn ibn Ali (a.s.) shall always remain an Imam whether he rises (rebelled against the oppressors) or not. He (s.a.w.) also insisted that the Muslims should love Imam Husayn (a.s.) and adhere to his teachings. Anyhow, it is well-known that Imam Husayn (a.s.) is the best person of his era after his father and elder brother. As it is known that Imam Husayn had rose up against the authority of Yazid ibn Mu`awiyah to fulfill his duty toward the Holy Quran and his Holy grandfather (s.a.w.) when he noticed that the Umayyad caliphs had exceeded the limits of Islam with their oppression and injustice. Imam Husayn (a.s.) followed the tradition of his grandfather, namely, "He who sees an oppressor and tyrant ruler, who is changing what is forbidden (haram) into what is allowed (halal) - those who broke their covenant with Allah and fight against the sunnah of the Holy Prophet (s.a.w.). And in the face of this he doesn't try to contest or protest against that ruler's illegal deeds neither by speech nor by action, Allah shall put him in the same place where He shall put that tyrant."

Some of the chiefs in Kufa announced that they would assist Imam Husayn (a.s.) and promised to help him in letters that they wrote to Imam Husayn (a.s.) while he was in Medina. At the same time, some of the companions, whom the Sunnis are still eulogize, like Abdullah ibn`Umar, Abdullah ibn al-Zubayr, Abdul Rahman ibn Abi Bakr and many others, didn't give their allegiance to Imam Husayn (a.s.). We should ask why? Moreover, Abdullah ibn `Umar began calling the people to pay allegiance to Yazid, preventing them from assisting Imam Husayn (a.s.)!This had been recorded by al-Bukhari (vol.IX, the book of riots, chapter:`if he said anything before the folk'), and in Musnad Ahmad ibn Hanbal(vol.II, p.48) [This narration was conveyed by Naafi`].
Now, we ask this question from the Sunnis: Do you disagree with Imam Husayn's uprising? If we search in historical records we shall come to the conclusion that the Sunnis had preferred silence and agreed to be with those who remained behind. But all of us know that whosoever remains silent - not support his Imam (a.s.),
knowing that the Imam, the son of the Holy Prophet (s.a.w.) is right - agrees with Yazid and his wicked deeds. Thus, these people shall be considered as those who have participated with Yazid's army and fought against Imam Husayn (a.s.) and were indirect partnersin the massacres of Yazid's army on the day of `Ashoora.
Infact, the rule of Yazid over the Islamic emperor was the continuation of`Umar, `Uthman, and Mu`awiyah rule.
Didn't Mu`awiyah fight against Ali (a.s.), and therefore the main factor of Imam Hasan's martyrdom? Didn't he submit the key of caliphate to his insane son Yazid, and by doing so breaking the covenants he gave to Imam Hasan (a.s.)?
We put these questions in front of those who assisted Yazid and stood with him. Those who remained behind and abandoned Imam Husayn(a.s.) in the hour of straightness, when he rose against oppression and corruption.I