I don't need to pull up the studys, they are out there and they aren't on your side here
I'm not saying WHY, obviously nobody can read minds, it is impossible to know the intent, we can only know the effect of said intent which in this case, is Oda promulgating filthy images and scenarios into his story and to his reader
We can't know why even conceptualize why a lolicon artist draws what they draw, but we can see that they do. And that it's wrong
His preference may be towards it or against it, what matters is the effect which is that it is a perversion of his character and story that has caused a reasonable outrage in the community for years, culminating in Egghead
Plus...even if we can't know with 100% certainty, we can still reasonably assume some things for example that he views Luffy as good and Along as bad based on how he potrays their dynamic, or that he portrays Nami as a protagonist and good person, whilst also having her obscene against 8 year olds, therefore we can reasonably assume that these are not violations of morale for a character that he would have a protagonist do it without remorse