It's creepo manga for sure but the events make sense here if you actually look at it from their view instead of what twitter (Bluesky) tells you to view things as.
Sci-fi realism angle or no, framing "supporting rape is bad" as an internet fad feels like ya really need to go touch some grass, mate.
And the author clearly didn't exactly write this as a piece of thoughtful examination of the tragedies that could arise from misunderstandings and values dissonance with an alien-cultured lifeform. The blobby boi is agreeing to keep quiet because the author thinks it's hot. The presence of an in-universe explanation might be a hint of good(???) writing, but it isn't really a colourable defense of the content being there in the first place. (Incidentally, why am I reading this? It's like being unable to tear my eyes off a train-wreck. Anyway.)
A colourable defense
would be that it's fiction and the author is into rape and that's actually okay so long as it
stays in fiction, really, and so long as everyone understands what's problematic about it. Well, except for the fact that people reading can get blindsided by it, which is what OC was complaining about, no? Which all is a good part of why specific content/trigger warnings and the like are useful communication tools (simultaneously A. tersely and effectively acknowledges
that the problematic stuff is problematic and B. lets people who don't want any part of it to just stay away), but that's not really an idea that's caught on in Japan last I knew.