There hasnt been one market that has tolerated the sale of childporn for as long as DNMs have existed, only recently has a CP-only market come up and guess what, its still running, not one 4chan script kiddy has taken to ddosing it or fed to taking it down. And thats great, because it means if you know what you are doing, Tor is secure.
Now in a couple years the community will move away from centralized markets to decentralized markets such as openbazaar, which among being seizure-proof and theft-proof, will also be censorship-proof, which means everyone will have to get used to the reality that the tools that make you safe, make pedos safe, and the tools that you use to get off they will use to get their fix too.
The fact is in the eyes of society and law enforcement, pedophiles and drug abusers are in the same camp, both take a toll on society that no one wants, even if it is your body your choice, so hate it all you want but there will be childporn right alongside your drugs right alongside their iphone accessories and cookware.
Let's make this more extreme, for the sake of argument.
OP: would you be okay with terrorism discussions? Let's say- guides on how to build weapons and perform covert operations against civilians of (where you're from) ? Paid-for terrorism services on DNM, such as 100 BTC for an anthrax attack against your city? Enriched uranium and plans to build nuclear devices?
I'm not saying there has to be a red line, but I'm wondering if specifically you have one. Absolute freedom can include many, many things.
EDIT: typo