As nice as it is to link to the actual interview, the blog post does so as well, and adds its own content to the mix. I don't see what's pasted or spammy about this.
It's to mitigate people linking to the same story 10 times.
However, if the additional content is noteworthy, then you could link to it on HN, but make the title accordingly specifying that it is the opinion of the writer, and not the original source, that is what the reader should be considering.