This is a gag manga, is made for the laughs, it knows what it is. Clearly not for it to be taken seriously, neither does it deliver any kind of hidden message.
It is simple, if you find the topic it uses for comedy uncomfortable I suggest you move on cuz it will just be more of the same.
... Did You even read what You wrote?
From what are You laughing reading this manga... From tortures? From 10 years old trap chained to the wheel and drowned in the pool?
Like bullies laughing from their victim being flushed in toiled with pants down? Nice... Clap... Clap... Clap...
So next time maybe everybody will laughs from rapes, murders, humiliation, pedophiles, wars, tortures, bestiality, scat, crucifixions, public executions... Choose Your subject of fun :) Why not :) Like in Roman Empire: "Bred and Games".
Just understood, that there are subjects, which can not be treating lightly! Because reality is far more worse, then some fiction, and evil is evil, does not matter that it have a sweet cookies! And We live in times, where evil is treated like a "style of living".
People laugh about crucifications since 1979. Pedophiles are the source of comedy in countless manga and anime. Murders are made fun off all the time, just pick up Deathpool or Murcielago or something. Rape is the number one joke material in like 50% of all Ecchis. Wars are played off as something minor or even fun in pretty much every Action Comedy. And humiliation is the only thing that WataMote is about.
Anyways, comparing laughing about a torture manga to having death games is pretty far off.
If you wanna get all serious about every little inappropiate joke then that's fine but you can't expect everybody to do the same thing. Again, Haruka going crazy over little children in Kanamemo is not the same as actual people being pedophiles. You either think it's funny or it's not but you shouldn't make it bigger than it is.