1. Muawiya's :ra: position was wrong in regards to Ali's :ra: decision not to punish those who assassinated Caliph Uthman :ra: this we know is a fact, however if we curse him for that that should then include Aisha :ra: , Talha :ra: and Zubair :ra: . Remember, Muawiya :ra: did not partake in the Siege of Basrah and the Battle of the Camel.
2. Though Muawiya :ra: did not recognize the Caliphate and defended himself at the Battle of Siffin (though seen as a wrong way to wage war in defense, perhaps out of desperation) did end up with a peace agreement with Ali :ra: and this resulted in the Kharijites to seperate from Ali :ra: and eventually the Revolt of the Kharijites under Muawiya's :ra: rule.
3. Muawiya :ra: in fact considered Ali (ra) above himself:
Look what the Amir said!
"Ali is better and more virtuous than me and I differ from him only in the matter of qisaas of Uthman and if he takes the qisaas of the blood of Uthman I will be the first of the people of Syria to make bayah to him" [al-Bidayatu wan-Nihaayah, vol 7 page 129,259]
Also Rasullullah said:
The Holy Prophet Muhammad (PBUH) had said:
“The first group of Muslims to make Naval Jihad will be the inhabitants of Heaven. “
-Under Amir Muawiyah the first naval ships were deployed!
