I disagree, but I think the real motivation may share a common root (again, talking about "most people" here, not the actual people doing the development). The common root is the invasiveness that governments have turned into standard operating procedure, much at the behest of big copyright holders (but not all; in the USA, the "war on terror" has been a huge motivator as well).

If you are going to throw a straw man out, do it right: child porn is the driving motivation for alternate Internets. Think of the children and don't let that happen!

Many people think that non-commercial, private sharing of arbitrary files with each other should not be illegal in the first place, and that enforcement of copyright is a form of for-profit censorship.

Those alternate internets are built with the general intent to guarantee informational freedom, disable censorship or at least make it more difficult, regardless whether it is Iran-style religious censorship, North Korea-style political censorship or US-style for-profit censorship.

Right, the free flow of information scares some people. The lack of it scares others.