Well, in your first example, that isn't protected speech. That kind of statement is an accusation masquerading as fact in order to cause harm (physical and/or non-physical) to a person. That's why it's illegal. If that same person said "It's my opinion that Stephen Fry is a pedophile." and omitted the factual statement of "I've seen his collection of kiddie porn" which is an outright provable lie (in your example), then who cares if he says that?

In your second example, why would you be offended if he did this to his kid? I don't think offended would be correct in this situation. Perhaps concerned for the child's health and well-being, but not offended at the words coming out of the father's mouth. I'm not sure if it constitutes child abuse, but if so then it should be reported.

In your third example, I would be ok with that happening because it's explicitly stated that it is this person's opinion. So yes, you'd be a "stick in the mud" to be offended. Now, I wouldn't be offended that she said it, but I would question her ability to make sound decisions in her position. Her opinion is incorrect (and yes, opinions can be wrong: http://www.overcomingbias.com/2006/12/you_are_never_e.html) and she should most likely be ousted from her role.

Specifically related to your last example, my opinion that she is not fit for her position and should be removed is not based on whether or not her statement was offensive. It is based on logical ideas of her competency and her views on society (no one deserves to get raped).