The racist part was the lack of sourcing for the statements above. I'm sure if the poster in question had stated sources for the various claims you would... Still call it racist?
Another question is why raise the comment? This could imply a prejudice. While the reasoning wasn't clear, it made me think that Africa is a source of radicals unless its education standard can be lifted.
I have little faith in most sites being able to objectively discuss differences, but HN is still better than most. I encourage people to challenge prejudice in a consistent way (eg. No free tickets on being prejudiced based on gender or skin colour, unlike what happens at The Verge and most other media sites).