> Why would blog posts not be subject to such criticism?

You're asking why casual comments from amateurs made for fun on the internet shouldn't be held to the same standard as those made by funded career academic experts writing for other experts over months and meant as part of the permanent record of the field?

Personally, I think that's a bit like asking why a friend having you over for dinner isn't always an elegant 7-course meal with wine pairings. I guess you can expect that if you want, but to me it sounds like a child expecting to go to Disney every day: ignoring the economic realities of the situation is a recipe for eternal disappointment.