I think people are missing the crux of the conflict a little.
The point about Lovecraft and Campbell is not that they're especially well-loved or eminent; the point is they have become where the "wait, wait, you can't include that in the critical response" pushback happens to have stuck.
Three things are currently true:
- there is far more art than anybody can apprehend
- the hegemon's legitimacy has collapsed
- tastes and canon are shifting, being reexamined, and expanding
One very plausible response to the combination is to say, right, possibly formative work, but if so, we're ashamed; this stuff is bad, it arose from a bad place, we should call it bad, and dispatch it to the ash-heap of history.
So far as I can tell, that response is becoming the dominant response in written SF; the expected writing standard has increased sharply, the predominant response to "yup, racist and sexist" is "never read their work again", the predominant response to "the author's personal conduct is repellant" is "never read their work again", and this has no effect on anyone's enjoyment because there is still so much really excellent stuff to read after you do this. (It gives me strange ideas about literary endeavours in the Culture.)
That's a direct threat to the sales numbers of lots of currently active authors. (I wish it skewed old. I doubt it does.) That's where the insistence that you must separate the artist from the art, that you can't use your opinion of the artist to judge the art, and so on, come from. Same with arguments of significance; if someone had an artistic response, it must have value and be accorded its due accolades.
Which is nonsense; you can almost sort of make that case if you're doing formal academic study, but when reading for enjoyment? Absolutely you are under no such obligation whatsoever. It is entirely fine to be heaving the classics of yesteryear on the ash-heap of your present.
 fixit fic; a huge chunk of fanfic is "yeah, that's bad, let's rescue the not-bad bits" response art. Note that this is precisely the opposite of "we will forgive the bad for the good in the original".