The issue I see with this post is that you’re acting like this is some common occurrence that people just take screenshots of other individuals’ characters in the nude and start harassing them with said screens—in the case of the OP, this hasn’t even been proven to be true; they made no mention of (prior to this thread) even being harassed by such things. Instead, it sounded like they heard about mods, dived into the Discord for them, got scared that they or other people are going to suddenly be targeted by a bunch of predators, and started a crusade (much like how the individual on Tumblr started theirs, but then again, it is Tumblr). I asked them if this had ever happened to them (and I believe a few others did as well), and they have never answered.
Modders mod for the sake of their own characters, not to see other characters naked. There are obviously skeevy/shady individuals in every community (note how I said every community, not just the modding community), so you deal with them as appropriate: report them, blacklist them, and then move on. You speak of perverts, but perverts don’t have to mod to still be perverts. Just saying.
Telling someone “you are not your character, and they are not you” isn’t the same as acting like your avatar is just a throwaway, valueless construct. My character is extremely dear to me, but I am cognizant enough to realize that she and I are not the same, and thereby an image of her naked is most definitely not the same as an image of myself naked (unless I suddenly became a Warrior of Light/Slayer of Eikons with cat ears and a tail overnight—in which case, ugh, I’m far to lazy for this kind of life).
The only way SE could actually identify modders if is they install a client-side detector that can detect when game files are read/modified. This would also get rid of ACT and ReShade, and, at that point, SE would be hurting their bottom line.