Without having seen a frame of it: one could get the feeling that one of the reasons they hate Goblin Slayer so much is, by having a rape scene, they can no longer write their multi-paragraph screeds about how the goblins are Good, Actually, how the straight man fighting them is the bad guy, how the show is racist for portraying the clearly BIPOC-coded goblins as evil when it's all colonialism's fault. But the goblins are shown raping, so they can't be in the right (and it would go against the narrative to equate them to another skin colour), and can't 'subvert expectations'.
Conversely, I get the impression that many defenders defend the anime not because they've watched or liked it but because they want to pwn the sjws. I tried watching it, but I couldn't stomach its sadistic violence (the goblins rape/murder underage teenagers, flay people alive and nail them to shields, etc), puerile treatment of serious issues, and the writing was generic and boring as hell.
It's not a good story. Aside from being puerile and edgelordy (I'd say "misogynistic", but that's lost all meaning nowadays and isn't taken seriously even when it would make sense to apply), the world building is both generic D&D clone (which has its own issues that are too big to tackle here) and its unique aspect doesn't hold up under scrutiny.
The 1d4chan page points out that you can't simultaneously depict the goblins as a big threat to civilization and as a harmless pest to the same civilization depending on whether it's convenient for the narrative at that moment, as that breaks suspension of disbelief.
On the other hand, I have seen people try to argue that the goblins are a racist metaphor anyway. "That other tribe wants to rape our women" being a screed as old as time immemorial. I don't see anything in the goblins that is specifically racist caricature against non-whites, unlike the painfully obvious
satire in
terraformars. (Fun Fact: GS started as a 2chan thread where an image of the terraformars was used to represent the goblins.) You could argue that they're a representation for the horrors of colonialism, in which colonizers (whether white, mongol, whatever) brutally subjugated and raped innocent indigenous peoples both literally and metaphorically. However, considering how generally mediocre the writing is I strongly doubt the author of GS was introspective or worldly enough to deliberately invoke that sort of discourse. (Whereas terraformers is so obnoxious that
I can't tell whether it's a
The Iron Dream-style satire or not. I certainly hope it's satirical rather than earnest, because otherwise that would mean the SJWs have a point. Sometimes.)
The biggest sin I can level at GS personally is that it isn't
WarCraft: Orcs & Humans. In that game, the orcs are conquistadors. Full stop. In the second game, they even recruit persecuted minorities to fight for them a la Cortez and the Aztecs. That's interesting, complex, nuanced, morally clusterfucked, very human-like despite being aliens from another world. (Ignore the retcons that they were innocent victims in the third game, that's war crime erasure bullshit.) I wish more orcs/goblins in fiction were like that, rather than the false dichotomy of either simplistic puppets of evil or poor innocent stand-ins for non-white people.
But if GS waifus makes your dick hard, then who am I to tell you what or what not to enjoy? In a few years it will be completely forgotten in favor of the next big thing like 99% of anime are, so there's really no point in caring very long. I'm personally waiting on the upcoming RTS
Edge of Chaos, which has orcs that raise humans as food.