It probably has more to do with the stated business rather than what's possible. For example, nothing is stopping you from going on whatsapp and, one hexadecimal byte at a time, writing out the entirety of a zip file full of whatever illegal stuff you want. Then, there's nothing stopping people from copying those bytes into a hex editor and recreating your stuff. This was used to great effect with DeCSS leading to the ideal of "illegal primes". The USG would have to ban typing any string of hex into anything to make this actually have teeth. But then you could move to binary, octal, brainfuck code that creates the file with shifts, etc.

But, with a company that hosts files you are liable for checking those files. There's also nuance here: you can't check everything all the time. You also can't check encrypted shit. But if you make no effort (see: the bar example) then that rises to inducement. Anonfiles, for example, is negligent in this regard. There's no law preventing you from allowing people to store encrypted files but there should be a way to not only comply with valid, warrant-provided, law enforcement requests but also keep track of such "prolific" uploaders as they are most likely uploading shit you don't want.

Source: I work in an industry that, unfortunately, has to deal with this stuff all the time. The internet is a sick place. Our legal team briefed us on our responsibility (in terms of storage and processing) along with the correct chain-of-command should something come up. Of course, we also have therapy available which is used more often than you'd think. In our case there's also some protection afforded to us for the things that may be stored because we comply with various law enforcement agencies when necessary. Posted further up you see:

> Recently, the last CP addict idiot basically killed us. We always remove those posts when we get a report (we can't see them by our-self, that's the point), but we were swamped by other things, and we didn't catch this one in time. It's a free volunteer project after all.

Which tells you they had zero idea what they were doing. If you're not hosting your anonymous service on an derelict oil platform deep in international waters you have a responsibility to get the correct legal counsel and set up a system for handling chomos. Ignorance is not an excuse, "volunteer" is not an excuse, AND you shouldn't make a service that protects chomos.