@GruntZone360:
As an aside, although I haven't read this and can't comment in this particular case, I think MangaDex has taken to using the "smut" tag differently than the places it took it from, as a general indicator of sufficiently-explicit sexual content rather than actually referring to things that are "smutty" in tone.
Demographic tags are the same as always, though, so probably just was clumsily tagged in this case as you say—again, I say this having not read it.