[theorique]

Additionally, Andy Grove, Elon Musk, and Sergey Brin speak very clear, understandable, and yes, accented English.

What PG actually said is that speakers with accents so thick that the YC team had to interrupt frequently to ask them to repeat themselves, tended not to be successful.

I think the problem was that PG used the term "accent" rather than "communication problem" or "could not understand what they were saying".

It's about the communication, not the fact that English is not their native language.