He did eventually “disavow” Duke. So the ruckus is really about why he didn’t do so instantly.
He had already disavowed last week several times and didn’t want to be dragged into the KKK tar pit again. Trump is guilty of being inartful. That is all.
I do not know about multiple times but he did in the first moment say he disavowed David Duke which is not overly surprising as he also listed Mr Duke as one of the reasons he left the ill-fated Reform Party.
The fact that later he seemed to walk that back a by not condemning groups David Duke might be involved with is problematic with multiple possible reasons the simplest being he just didn’t know the groups were bad the next simplest being he just didn’t remember we said earlier and the next most simple being he just extemporized badly. I do not like Mr Trump I do not like him as A candidate in any way but unless one takes the entirety of the event you get a skewed view. What do I think he meant I do not know you the same but as a candidate his statements have been so vague and/or were self contradictory that this has become an issue.