That's conflating data formats/requirements and offensive political content. Protocol defines data formats, it (in most protocols) says nothing about ugly content.
You can have permisionless protocol without censorship.
Discussion
Invalid bitcoin transactions are writing
They are suppressed on all nodes that follow the bitcoin protocol
Because they are considered unacceptable
I know that you will bend definitions as far as you can to make a point, but the bending is what diminishes any value of the point.
Not allowing 3D videos in hardcover printed paper books is not censorship.
If someone found a way to do it but couldn't only because book printers refused to print books with such videos in them, that would be censorship -- even if they decreed that they were following a certain "book printing protocol" and blamed the prohibition on that protocol
As for "bending definitions," I don't think the way I apply the definitions of words counts as bending them. I apply them in ways that highlight counterintuitive realities to demonstrate that there *are* counterintuitive parts of reality that fit the natural definition of things you might not expect them to.