I do not doubt that there may be correlation between people who have performed poorly in YC and "very strong accents", it does not mean causation. Such a statement from someone whom people hang to his every-word should not be put out without clarification.
The defense of "accents so strong you cannot understand" holds no water. It was an after thought. What about people that are dumb and cannot speak at all? Nothing could have stopped him from saying "people who do not communicate well make bad CEOs. As an example, thick accents, stammering, unclear minds can be the cause.
Instead of clarifying the context which I assume to be "With a strong accent you will find it to raise money on demo day which is very important" or expanding it, Paul Graham goes "Don't say things people want to misunderstand"
It is insulting at best. Heaping the blame/responsibility of understanding on the readier/listener. How ironic considering the topic.
I hope his position does not lead to default bias in YC companies. "He has a strong accent, I cannot ask him to be my co founder". Or "His strong accent means he will be a bad CEO so why employ him at all"
This tread will soon disappear. But I will end with a Martin Luther King quote from the I have a dream speech 5o years ago yesterday. "Our lives begin to end the day we become silent about the things that matter"