Immature. Lewd. Low-brow. Predictable.
You could call Shimoneta all these things and you wouldn't be wrong. But there is an underlying complexity to this.
Let's start from the beginning:
Shimoneta takes place ten years in the future where legislation has been passed to illegalize all pornographic material and profanity to promote morality.You do have to kind of suspend your disbelief for a bit to let that premise to sink in. But once you do, you see what problems that would bring.
Early on the anime demonstrates the dangers of having pubescent teenagers who are uneducated to sex.
False information gets spread and children have no way of coping with their urges. Not only that but "erotic terrorist" organizations begin popping up in protest. Most are peaceful but there are many who aren't.
We follow S.O.X. a newly formed organization made up of a daughter of an arrested politician who enjoys dirty jokes, the son of an "erotic terrorist" who was arrest about a decade before the events of the show and an prodigal artist student who feels like she has been limited by her inability to draw the human body. Their usual operations consist of distributing pornographic material, yelling swear words and drawing depictions of genitalia.
Throughout the latter half of the show they make a heavy emphasis on the difference between peaceful protests and violent uprisings. Which seems to be the true core of the story.
I highly recommend this show.