We empathise with others when we are able to imagine how they feel. To empathise with the McCanns is remarkably easy, because they have told us how they have been feeling ever since their daughter was allegedly abducted. All people need to do is believe in the stranger abduction. It's not so easy for those who doubt that is what happened.
There are individuals who have no empathy for a child who went missing when she was three and who have striven over the sixteen years of her absence to ensure that every initiative taken on her behalf was obstructed.
That starts with objection to fund money raised to finance the search for her when only her parents were keeping the investigation alive. It continued in resistance to her parent's attempts to have her case taken up by the British authorities and investigation started.
Where the malice and lack of empathy will end - I haven't a clue. But the difference in attitude and empathy shown to desperate parents and the suspect in Madeleine's disappearance who happens to be a burglar, convicted rapist and child abuser, is very marked.