You are intolerant of people who do not agree with your views. There is no contradiction.
Chaucer wrote in late Middle English, which was also very different from Modern English ('modern English' has a different meaning from 'Modern English', btw). Even with early Modern English users like Shakespeare, spelling was not standardised (think about how many different ways he spelled his own name!), so the spelling is not a reason to reject it. There are plenty of other reasons, the primary one being that it would not be an effective way of communicating as people would be unfamiliar with many of the words and references and grammatical structures (and also it takes too long to hold a conversation in blank verse)
As to authoritative sources, obviously in English there is no equivalent of the Acadmie franaise, so there is no overarching authority to say what is and is not acceptable English. This is one reason why English is such an adaptable language, but it is also problematic as effective communication depends on a certain degree of standardisation. The OED is often considered the authority on British English vocabulary, but there is no similarly regarded work on usage. However, I can say without fear of contradiction (by anyone but DadDadDad) that 'somebody's blog' is not in contention to be this authority. At best, a blog can point you towards properly researched and reviewed sources to support what it says. More usually, it just presents somebody's opinions, and I'm sure you know what opinions are like, and how seriously you should take them.
As it stands, English as a language is essentially governed by consensus. I think most people want to use 'correct' English, and I think most people 'know it when they see it'. There are, of course, people who actually study this, the evolution of languages. Their academic papers are certainly more authoritative than 'somebody's blog' (even if the blog is written by the same person).
BTW, I am not actually an old-fashioned pedant. I am a dialect speaker and a lot of the things that seem to annoy pedants are not incorrect in my dialect. Others are incorrect in my dialect, but are acceptable in others. My biggest bugbear is incorrect pedantry (e.g. people who think that 'John and me' should always be changed to 'John and I'). I think that for the most part, in an informal setting, scrupulously correct grammar or spelling is not essential. Sometimes there is an error which changes the meaning of what is written, but that is comparatively rare.
Nonetheless, I think it will be a sad day when nobody cares about the difference between there, their and they're, or gets annoyed that so many people seem to think that should of is correct.