I totally agree that not addressing issues and not bring (constructive!) criticism is a poor strategy. But your persons A and B have the same problem: they're critical without being providing any actual information. Person B just compounds it by also being a jerk.
As a programmer/businessperson, I'm not interested in making people feel good about poor quality work. I'm interested in people who want to improve themselves and the overall product, and ideally, enjoy the process. I just don't see how insulting code or people helps. I think it's perfectly possible to hold high standards on code and respectful conduct, and it's perfectly possible for people to rise to those standards, guided by constructive criticism.