As far as I know this all started with a valleywag article a couple days ago, that somehow turned (paraphrased) "Something we've noticed after funding 500+ startups is that people with difficult-to-understand accents have trouble raising money and recruiting cofounders/employees" into "Paul Graham is a racist xenophobe who hates immigrants, pregnant women, and probably non-white people too."
All other things being equal, there is a lot of difference between what an eloquent speaker can achieve and what a heavily accented speaker can achieve in the role of CEO.
This has nothing to do with preconceived bias. This has to do with Paul Graham's examination, over the course of funding over 500 different startups and his experience in that entire domain as a whole, that foreign accents are not desirable. The data is there; your bias prevents you from seeing it because you're misinterpreting it as discriminatory.