Lewis Carol did not molest Alice Liddel (At least from what I've read).
Here's the story:
On July 4th, 1862, Alice Liddell asked Lewis Carol to entertain her and her sisters. This was a rather long boat trip, I suppose, because in that time, Lewis came up with the story of Alice and Wonderland - or at least an outline of it.
People claim that Alice, the herione of the story, is based on Alice Liddell, but Carol himself has denied it (But it is also known that he meant the White Knight from Through the Looking Glass to represent himself and his relationship with Alice).
Now, Carol was a photographer and in that time, photographing children - naked even - was seen as innocent. All what you needed was the permission from that child's parents.
As stated, these pictures were not seen in a "dirty" way, nor were they taken with mal-intent.
Here's some concrete:
"...that perceived child-nudity as essentially an expression of innocence. "
"Hugues Lebailly ... has pointed out that child nudes even appeared on Victorian Christmas cards — implying a very different social and aesthetic assessment of such material. Lebailly claims it has been an error of Dodgson's biographers to view his child-photography with 20th or 21st century eyes and, to have presented it as some form of personal idiosyncrasy, when it was in fact a response to a very prevalent aesthetic ... ideal...."
I hope that helped.
And please, never think that an artist's creation is rubbish just because of his or her personal life.
The creator's personal life should never detract from the work .