To the first, I agree. To the second, I'm mixed. I mean, I hear what you or someone else said upthread, that we usually end up talking mostly about the work, not the author (someone used the example of the Wrath of Khan's writer, which I thought was apt). On the other hand, it also depends upon how deep we want to go, and also how clearly we want to understand the world and the author's intention. At the very least, it is interesting to understand the context of an author's life, and might shed light on their work.
For example, when I read Tolkien's biography (or maybe Letters) a couple decades ago, I found it interesting to discover that his depiction of Mordor was inspired by his childhood in the Midlands of England, and the industrial landscape that he grew to detest and contrast to the woodlands that he loved. It deepens our understanding of who he was, and why he contrasted the beauty and light of Aman and elves vs. the dark ugliness of Mordor and orcs. Tolkien was deeply Romantic (in the capital R sense of the word), and yearned for a "golden age," which we see glimpses of in the LotR but is more fully expressed in The Silmarillion.
To him, the "creatures and lands of evil" were at least partially expressions of industrialization and the perversion of nature (Jackson captured this with his depiction of Saruman's industry, and the consequent "revenge of the ents"). This also contextualizes any racial connotations as being more "burps" than defining statements. He was more interested in the use and misuse of power, and the degree to which mortals either aligned or distorted the "song of creation." Thus Melkor, the primordial adversary, singing in discord with the song of the Ainur (although Tolkien hinted that this discord may serve a greater purpose in Iluvatar's plan).
I digress a bit, but I think it serves my point: that understanding the author deepens one's understanding of their work.
And if we want to understand Tolkien, that's great. But, if I want to critique The Lord of the Rings, for example, Tolkien simply doesn't matter. We can examine LotR in the context of the time it was written, but, largely, any interpretation of LotR has to be based in the text itself.
Anecdotes from the writer's life might be interesting, and, they might spark a talking point, but, unless we're actually discussing the author and not the works, the author's life is largely irrelevant to understanding and interpreting a work. Sorry, J. K. Rowling, no you don't get to after the fact declare Dumbledore to be a gay character when there is absolutely nothing in the text to even suggest his sexuality in any direction.
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On the topic of the vitriol regarding Lovelcraft.
One has to remember that Lovecraft was, until very, very recently, given a very prominent place among the authors of the genre. The 5e PHB, published not that long ago, places Lovecraft in the list of inspirational authors alongside Tolkien and other great genre authors. Heck, the term, "Lovecraftian" is used to describe works, completely expunged of any racist meanings. Think about that for a second. You're a writer who Lovecraft would have thought should have been castrated or killed, and your works are being called "Lovecraftian". Additionally, you're a really, really great writer and you win the highest award for Horror out there - the World Fantasy Award - and you are given the bust of a dude that would have thought Hitler didn't go far enough.
And, until very recently, if you complained, you would get reactions like you see in this thread - oh, you have to understand... it was just a product of his time, we don't really think like that anymore... you should be thicker skinned about it... we have bigger issues to worry about... hey, you just won a major award for your work, you should be grateful...
So on and so forth.
So the vitriol we're seeing today isn't really any different than the vitriol you would have seen in any other year. Thing is, instead of being pushed aside, sidelined and ignored, people are actually
listening and actually making changes - the bust of Lovecraft is no longer the World Fantasy Award. I will be pretty shocked if Lovecraft's name appears in the newly released 5e PHB under inspirational reading.
The vitriol is largely a reaction to the privileged position Lovecraft enjoyed for nearly a century, simply because he was white and only attacked minorities.