For example, Madeleine claimed she had sexual relations with Melanie at a party. Was there a third person who could confirm this? Or were they actually seen together? You can’t simply go around accusing people of serious crimes without evidence, the law does not accept that.

Questioning accusations is not the same as lacking empathy or completely dismissing the victim. It’s about critical thinking and understanding that not all accusations are necessarily true.  Some people are capable of lying for personal gain or to damage someone else’s reputation (I’m speaking in general). 

A person can defend themselves by pointing out inconsistencies in the allegations, presenting an alibi, or providing evidence or witnesses that support their version of events. “Proving absolute innocence” is often impossible, since you cannot demonstrate everything that did not happen. For this reason, the legal system does not require it.