I would suggest that the play shows that uncompromising idealism of the type that does not recognize the complexity of life, can sometimes do as much harm as good. Of course it's not that simple. Chris is, in some way, responsible for his father's suicide. I understand that not everyone may see it this way, but I think that some sign of forgiveness from Chris would have given his father a reason to continue even if he had to acknowledge his guilt. It's the opposite of Joe who refuses to see the complexity of what he did until he reads the letter.
The same situation exists for Dr. Bayliss, although he is able to compromise his ideas. His wife blames Chris and his idealism for her husband's unhappiness with his work and his desire to go into research. Once again, idealism gets in the way of life.