As maybe the main culprit behind such content, I can comment.
I'd love to err on the side of caution. Unfortunately that isn't how the NSFW toggle is used, and erring on the side of caution any more than necessary comes with drawbacks in terms of post visibility and community growth.
Posts like the one you linked perform orders of magnitude better when not marked NSFW, which means they reach more people who want to see them when un-tagged, than didn't want to see them.
And tagging them, in fact achieves the opposite.
This is because people scroll past content marked NSFW regardless of what it is. Because they can't see what it is. Except when they are looking for porn.
So while I didn't stop using the NSFW tag, I pushed the needle a bit and stopped marking everything even slightly revealing as NSFW "just in case" because it was literally hiding it from the people who wanted to see it, and leaving just the porn enthusiasts to check the actual images, who'd then down-vote it because it wasn't actually porn.
I am myself completely uninterested in actual pornographic content on Lemmy, yet as someone who doesn't mind it, I actually do not hide NSFW content, and even disable blurring it by default.
Because the binary tagging of NSFW is utterly useless as a tool for curating away content I do not want to see, as a SHIT-TON of content I DO want to see would go with it.
Instead I use the list view in Thunder with its small thumbnails, making the occasional porn very difficult to spot over my shoulder, but allowing me to much more properly vet what posts I open and view in full size.
I am fairly certain that a lot of the people who engage with my many "moe" communities, are, like me, quite uninterested in actual explicit content. As such they do not engage with posts marked NSFW, or perhaps even disable it entirely on their accounts.
The NSFW toggle isn't enough, and its purpose and exact threshold varies wildly depending on your sensibilities.
This content isn't porn, yet if I run my communities as if it is, they don't get traction.
If I run my communities like they're for porn, they'll mostly be frequented by people who post and look for exactly that. But they won't fit in because I don't allow nudity, and the stuff I do allow isn't the kind anyone settles down to actually get off to, despite some of it being arousing. So, my communities don't belong on that side of the fediverse, but at the same time they don't entirely belong on the SFW side of a lot of people's feeds either.
Yet, to reach the people like myself, but who unlike me don't make the insane effort of checking every NSFW post to see if it's not porn, that's where they have to exist.