Of course not. Unless this someone affirms he/she can do better.
Then this someone could be asked to provide proof about his/her statements, be it video, witnessess, personal interaction, etc., you know... the usual means for proving claims.
Not necessarily. Consider for example people who are eager, for reasons know best only to themselves, to expose their lives on Jerry Springer and similar TV shows. According to this logic one should not criticize them without providing a supporting video evidence proving that one could do better.