Seems to me some of those Writers were being facetious.
Don't have children! Don't read! Don't write long sentences, and write when you are drunk. Really? Let me add my writing advice: Weigh all writing advice on the scales of common-sense.
No, they were serious, and if taken the right way, it's all good advice. And he didn't say don't read, he said stop reading if you've already been reading for a lifetime. That is silly and unnecessary, but the way he meant it is not. No advice is written in stone, except for Bradbury's, but when taken the way it's intended, all this advice is golden.