I dunno, that Kate Smith stuff was pretty damn racist even at the time. I don't think every incident that happened in the past is necessarily a sign of real racism, but those songs Kate did were pretty awful.
I've never cared for Howard Stern much. He's never been that funny and he's pretty much a perpetual 12-year-old looking for attention. But just using the N-word won't make him a racist. It depends on how he used it. Pretty much anybody who's subjecting themselves to him won't flip out that much over it, his whole act is just cheap shock-value junk. Don't care about his books, one way or another, though.
Tarrantino overuses the N-word because he thinks he's being "edgy." I don't think he's racist... just juvenile. I like some of his stuff, but overall it's a little too corny. And if you're really well-versed in film you can see he's done pretty much nothing that's really original -- he just re-makes scenes from movies he likes and strings them together. I'm about as hardcore a movie-head as he is, so all I see when I watch something like Kill Bill or Death Proof are scenes strung together from old Lone Wolf and Culb and Lady Snowblood and Fists Of The White Lotus, Vanishing Point, Gone in 60 Seconds, Bullitt, etc. He even stole music from Lady Snowblood and used taglines from the poster of Bury Me An Angel as (very awkward) dialogue. Hell, even the title of Inglourious Basterds was stolen from another movie. He's not a filmmaker so much as he is a recycler. It's pretty much all video fan-fiction. He's fairly good at it, though, has a good sense of style and all, but there's no originality in any of it. If you've seen a few obscure spaghetti Westerns like Cutthroats Nine then things like The Hateful Eight feel like reheated leftovers. Even Reservoir Dogs (pretty safely) counts on you never having seen Day of the Wolves or Kansas City Confidential... which I had. If you don't actually watch a lot of old grindhouse movies, Tarrantino's more impressive. As is... eh. The finale of Lightning Swords of Death (a.k.a. Baby Cart To Hades) blows the big massacre in Kill Bill (which is trying to imitate it) out of the water.
A friend of mine used to be in the business (mostly casting reality shows) and he knows Tarrantino, and is constantly amazed that Tarrantino isn't dead yet. He's a basket case in real life and barely coherent at this point from all the substance abuse. Same with his buddy and sometimes-boyfriend Eli Roth. At least Eli Roth stuck a sequence in the credits freely admitting that he stole everything from Cannibal Holocaust, Make Them Die Slowly, Man From Deep River, Slave of the Cannibal God, etc.