I think this will either be ineffective, or simply make it even harder for people to know what they can post and what they can reblog. Although Matt's concerns about "porn bots", which are almost always a scammy way to get you to sign up and pay money off-site, are valid concerns, the fact that the proposed changes would allow me to write an erotic Overwatch fanfic but perhaps not post a drawing of two of the characters going at it is confusing.
Use of the word 'erotica' is particularly telling here, as it seems Matt has the innate ability to distinguish high brow from low brow pornography.