AI alignment is sort of like computer security except computer security is a real pressing problem and AI alignment is based on science fiction.
It seems to me that you should engage with the substance of your coworker's argument. Reading about something in science fiction doesn't prevent it from happening.
From what I have observed the reaction of most people working in the AI to "What do you think of Yudkowsky?" is "Who?". He's not being ignored out of pride or spite, he just has no qualifications or real involvement in the field