Just to be absolutely clear, there is foundationally no expectation whatsoever that either PieFed or Lemmy are trying to make a "free speech" platform. Truth Social and 4chan seem to already have that covered...
Rather, the owner of the instance (aka the one who pays for the machine and in all likelihood has to register it with their irl credentials within its country of residence, for legality purposes e.g. CSAM) gets to decide all of the rules that govern it.
If someone wants to use the Threadiverse to e.g. spread CSAM, they are welcome to make a fork but that's not what either PieFed or Lemmy (or Mbin, Mastodon, nodeBB, etc.) are about.
Anyone is free to say whatever they want, but none of this software is not bound to have to offer a platform to send those thoughts out to everyone, particularly those who do not want it.