My point is, with you it's always the same. Who do I believe, the great oracle muawiyah or my own lying eyes?
The only way you can deal with these problems is get a source in Spanish from somewhere in the Hapsburg sphere of influence and another in English or French ~ and see if you can figure out what the truth was.
BTW the Turks also had a major interest in the goings on in England and Spain and sometimes you'll see one of their versions infiltrating into the history.
So, you want to believe that the same Spanish government that was suppressing slavery was supporting slavery?