Stealing an entire article is not allowed even if you cite the source. It’s like stealing from Walmart and selling the goods with a sign saying “stolen from Walmart”. It does not make it ethical. I haven’t downvoted this blog, as others have already done it.

I don’t hesitate to downvote plagiarism when I find it, even if the source of the theft is mentioned.

It is OK to write a blog talking about what someone else wrote. You can include properly sourced quotes from that blog, maybe a few words, a sentence, or even an entire paragraph, to illustrate your point. It is definitely NOT OK to copy the entire blog, with or without mentioning the source.

@therealwolf is 100% right on this.