SJSinNYC
You are 100% right, but talking doesnt affect the neshamos, it can only distract others listening to Kaddish to answer and its actually a very improper thing to do. People do not appreciate the value of Davening in general. Kaddish suffers along with Chazaras Hashatz and leining.
Im always bothered when I see people who look like they had a proper yeshivah education, some even are in Kollel or look like learned people and they will talk during Chazaras Hashatz or Kaddish. However my opinion is it is a general feeling of disconnection from Tefillah.
I have a theory and I hope Im wrong but to me it seems that most people dont believe Hashem is listening to their prayers or they dont believe that their prayers even mean anything or have the power to accomplish great things and therefore why bother Davening with Kavana or caring about Davening too much or the fact that one can be disturbing anothers Davening.