I suppose, if one was to think of Allah as a regional tribal arab deity, then you would be right. After all, this is how secular historians view Allah and Muawiyyah- the regional deity of a regional tribal leader- who got lucky. However, if we think of Islam as a religion for all humanity made by the God of all humanity, then we may think of Muawiyyah and his family as the people who botched things up- the ones who established Islamic institutions that defined Islam in such a narrow, regional/ tribal way- that it divided the Muslim nation into an Arab and non Arab world. In which case, it could be because of him and his family that eventually,** their version of Islam was unable to impress all humanity as the religion of the One God of all humanity. That perhaps it is because of their corruption of Islam that followers of his relgion are being chased like animals in Afghanistan, Pakistan and Iraq by the Christians who should have been Muslims today**, if the correct Islam vision of Islam had been introduced to the world. Perhaps Muslims would not have been kicked out of Spain a year before Columbus discovered the Americas and the Americas would have been Muslim too, if it were not for Muawiyyah and his clan misunderstanding Islam.
I am not suggesting this is necessarily true. I am simply saying a lot depends on one's perspective. As the great sage of the world once said, We shall see.
Perhaps thats the reason why Prophat (s) said: 'When you see Mu'awiya on my pulpit, kill him!'