If Uthman were lenient in this matter...
If Uthman were lenient in this matter, which ultimately lead to his death and lead the Islamic nation to the greatest affliction and caused blood to run like rivers, then Mu'awiyah wanted to cut this affliction from its roots by killing Hijr" If Mu'awiya wanted to kill Hujr in this way to quell sedition, how is it that he was in effect willing to provide immunity to Hujr and his supporters if they cursed Ali.
This 'transgression' and attempt to corrupt the earth would have been eliminated by the act of cursing Ali (as)? This is the bond of the Muslims that Abu Sulaiman claims that Mu'awiya was trying to protect, a bond that could only be maintained through the cursing of Ali (as)! Now let us turn to the 'method of punishment' that of burying the associate of Hujr - Abdur Rahman bin Hassan alive.
Since Islamic Sharia prescribes clear methods of penal punishment, could Abu Sulaiman cite a single verse of the Qur'an or hadith that states the punishment for sedition is live burial? If Hujr was indeed a troublemaker as Abu Sulaiman suggests then one assumes that this action would have received widespread support by the Sahaba and tabieen, and yet we find no such evidence. On the contrary, we find clear condemnation.
Maudoodi in "Khilfath wa Mulukiyyat" page 160, states: "This incident shook the heart of the Ummah. Upon hearing the news Hadhrath Ibn Umar and Hadhrath Ayesha were aggrieved. Hadhrath Ayesha had previously written a letter admonishing Mu'awiya. Later on when she met Mu'awiya she said Mu'awiya did you not fear Allah even slightly when killing Hujr?'.
When Hadhrath Mu'awiya's Governor of Khurusan Rabiya bin Ziyad heard this news he shouted O Allah if in your knowledge there is anything good left on my part, take me from this world'. [Khilafat wa Mulukiyaat, chapter 5, page, 165 citing Tabari vol 4, page 19 to 207, Ibn Athir, vol 3, page 234-242, Al bidaya wan Nihaya, vol 8, pages 50-55, Al-isti'aab, vol 1, page 135] You can see the clear contradiction in the way Abu Sulaiman writes.
If the Sahaba like Ayesha, Talha, Zubayr rebel against Khalifa Ali (as) it is on account of ijtihad for which they will be rewarded, the same approach is NOT applied to Hujr. If he opposed Mu'awiya. Why is Abu Sulaiman condemning him? Can it also not be deemed that he exercised ijtihad for which he will be rewarded? If not, why not? Is there one rule for those that oppose Ali (as) and another for those who oppose Mu'awiya?