Not sure. Can you elaborate a little and I'll give it some thought? It was quite a while ago and I don't tend to spend too much time thinking about Spanish cultural activities from hundreds of years ago through a modern lens, so my thinking on it is a little rusty.
Why did blackface originate in Spain as a cultural tradition? I think if you remove intentionality from that question, it's hard to come to a useful answer, never mind a complete one. But I've not given it a lot of thought.
I don't think we should discard intentionality completely, but in the current context, absolutely, if Justin Trudeau was to say "I didn't mean it in a racist way", most people would laugh it off. Most others who wouldn't, are using Trudeau as a vehicle to defend their own actions - past or present. Removing intentionality from the discussion completely now has some small downsides, but it does have broad benefits that make it worthwhile. I'm not sure the same approach can be applied to explaining the origins of these things from hundreds of years ago.