I can see why you might think this is a good heuristic---don't trust blog authors who don't know the right names for common typographic symbols---but in this case I think you went wrong. Daniel is an excellent computer scientist, with a talent for writing straightforward papers about difficult topics. He's also a non-native English speaker who is usually very gracious about accepting corrections to his normally excellent prose. In this case, it was probably just a typo. It's already been corrected---likely because of a comment on the post. But if you ignore everything that contains small temporary errors like this, you're probably missing out on a lot of otherwise good articles.
I can see why you might think this is a good heuristic---don't trust blog authors who don't know the right names for common typographic symbols---but in this case I think you went wrong. Daniel is an excellent computer scientist, with a talent for writing straightforward papers about difficult topics. He's also a non-native English speaker who is usually very gracious about accepting corrections to his normally excellent prose. In this case, it was probably just a typo. It's already been corrected---likely because of a comment on the post. But if you ignore everything that contains small temporary errors like this, you're probably missing out on a lot of otherwise good articles.