It all depends on how you view abortion. Understanding that Dr. Pell and many of his followers believe that abortion is murder, he was stating that Murder is worse than Rape or Molestation. I see nothing wrong with that viewpoint, although I personally don't like making generalizations like that. For instance, when I was about 5 or 6, I had a disgusting teenage girl use me to practice "making out" with and other sexual deviances. I was technically molested. I think any murder, including abortion, would be worse than that, as I was not traumatically affected. However, if you take a man who has molested several children in ways we don't need to discuss and, let's say, a man who murders someone he finds raping his wife. I think the molestation would be a worse crime. In the case of these comments, being focused on abortion, I still think it is too general to categorize the level of sin.
Abortion at least ends with only a single lost life (which is horrible) but molestation can lead to many more.
Yes, but is abortion a more commonly perpetrated "sin" than molestation? If so, that would mean that more lives are aborted than lives that are molested and, again if so, I'm sure that was behind the thinking of Dr. Pell.
The other factor to do this is that we do not know the full context of these comments. The media is not exactly trustworthy.