I learned the old approach to order of operations and wasn't aware how it was possible for conventions about order of operations and interpretations of symbols could have changed in mathematics in the last thirty years. After all, math is math and not amenable to any changes, right? Well, as the article explains, the math part isn't but our slippery use of symbolic language has.
This is why we need pedants on the subject of language and usage, isn't it? Somebody has to care about exactly how words get put together and that's why all writers need editors who edit. :)