Blah blah blah. The distinction between prescriptive grammar (the stuff of grammar Nazis) and descriptive grammar (what people actually say and write) has been made for a long time. That doesn't mean that any English is correct if someone says it, or that some use of English isn't better than others.
Some use English unintentionally in ways that are imprecise, ambiguous or hard to understand and that is wrong. Some use English in ways that are ugly instead of beautiful and that is bad. Even in the absence of absolute rights and wrongs, there are still standards to which we may aspire, and I reserve the right to criticise those who are sloppy or lazy.