I just took the word as it was, I didn't know anything about the Thermians since I didn't watch the video before; interesting.
I would however argue that fictional works are representative of ideas. There is always some meaning to what a human says, does, creates or writes. Even if only subconsciously, an author writing a story about orcs raping women, men doing the same and no character trying to correct or fight it, will more likely than not not have a good relationship with women as a gender and it tells us about the author's mind, not necessarily his opinions.
Calling it the 'Thermian argument' then is honestly misleading at best, so I agree with you.
This is getting into semantics, which I don't like, but I need to make this clear so we don't talk over our heads. Fictional works are representative of ideas in terms of portrayal or depiction. One of the definitions of "represent" is to portray or exhibit in art. I went by the definition of "to serve as a sign or symbol of". Fictional works aren't representative of ideas in that sense because obviously, a story that depicts slavery, for instance, isn't really a symbol of slavery.
As for citing in-universe rules - let's just say that usually, people can differentiate between bullshit and honesty. If there is an in-universe rule that tells women in anime to bend over when piloting mechs and frequently stripping, then that is bullshit and I'm pretty sure most people would agree. I wouldn't accuse the author of sexism though. I would just think his ability to write compelling stories is poor as he seems to be a victim of his own carnal desires that stops him from doing meaninful work. In the end, I will watch it as some kind of satire or not watch it at all, and doubt people's mental capabilities if they think it's good storytelling.
The author's ability to write compelling stories is poor if he prioritizes fanservice over story-telling. Titillation is not a bad thing, but if that becomes the focus over the plot, then the audience will disengage and not care anymore. However, we see something like Kill La Kill which is rife with fanservice, but manages to tell a compelling story.
The 'Argument of Continuity' wouldn't fit what Dan is trying to describe, if I understand you correctly here, as his view is that the created universe does not justify the creator's intentions. and I would agree there. Universe (facts) and the window through which we look into the universe (written word, television, games etc.) are two distinct factors. The other way around, however, is valid, as the author's intentions will be related to the way he creates said universe.
Though that will largely depend on what the author's intentions are and the audience's role isn't exactly to be mind readers. We do know that the authors' ultimate intentions are to write an engaging story and the audience will judge their works according to that standard as that is the standard we can all agree with. Anything beyond that will become too subjective and decentralized. However, we can tack on additional standards depending on the genre of the work such as if it's erotica literature. The point of erotica literature is to titillate as that is the nature of the genre. In fact, this perfectly segways into my next point.
In a situation like the orc-raping-women story of the video, the backstory of why the orcs do what they do has nothing to do with how the author portrays said situation (pornographic display). Therefore the entire chain of arguments is invalid and the foundation for discussion is void.
There are two issues with this line of reasoning. The goal of pornos is to titillate and by definition, pornography is sexual material for the
exclusive purpose of sexual arousal. If the orc raping women anime is strictly pornography, then it is rather pointless to judge the content based on effective storytelling as that is secondary to a pornographic work's goals.
Secondly, describing the scene to be pornographic is presumptuous. You first need to consider any alternative viewpoints before making such an extraordinary claim. Ever since Goblin Slayer aired, Dan claimed that the series perfectly matches his orc example. I would have to vehemently disagree.
When Fighter Girl got her clothes ripped off and pinned down by the goblins, you would think it was just a scene meant to titillate. However, it's used as a dark foreshadowing tactic. A girl whose clothes got ripped off and is forcibly subdued by a bunch of goblins. Do the goblins intend to beat her to death? Well, no as they would've done that immediately like with the other rookie adventurer. In hentai, characters who are depicted in the kind of pose Fighter Girl was forced into implies that intercourse will happen after. Even if the person never watched hentai, however, he/she can still put 2 and 2 together as a sexual pose implies something sexual will happen soon. And the series confirms this as the goblins proceeded to rape her.
Was this scene pornographic, i.e. was it exclusively meant for sexual arousal? Not really. It was meant to show how vile creatures goblins are and how low they will stoop when met with a vulnerable girl. Now, one would say that this is not a good enough justification because this is just for the sake of being edgy. And I would agree with that. However, later in Ep 1, we discover the reasons why the goblins rape women. When Goblin Slayer and Priestess rescued the captured women, Goblin Slayer discovered a hidden room with goblin children. Piecing together the puzzle, the audience will realize that the goblin children came from the victims and that the victims were used as goblin baby-making machines. The point behind the rape scene was not for sexual arousal, it was to reveal a very dark Darwinian truth.
A YouTube comment of the original video sums it up pretty well
The question to the author in this case wouldn't be : why are the orcs doing such a vile thing? It would be : why do you portray such a vile thing in a pornographic way?
But then, I would have to ask how do you know that the scene is portrayed in a pornographic way? Have you considered the alternative arguments and their merits before arriving at your conclusion?