The "federated timeline" and "hashtags" are public spaces in the #fediverse
. It's like the open public plazas of old or our modern rules about sidewalks/streets. Do whatever you want, say whatever you want, as long as you keep civil and not violating any Human Rights. If it's somethong that should be hidden, either move to an instance/server/node/pod/hub that federates with no one or a few; or use tags that will trigger the appropriate filters.
We can not and we should not police the fediverse, regardless of network/protocol. Many of us go out there convincing people to switch over, "advertising" the federated decentralised world, that they can choose whichever server that fits with them, then boom, the unsanctioned "federated timeline police" starts dictating to people in other servers what they can and can not do.
Police your own server/instance/node/pod/hub not the Internet. Your policing does not extend beyond the boundaries of your own, telling other admins what their users can do and can not do. It doesn't matter which network/protocol you are in, it applies to all. It applies to the Internet itself. My server, my rules; his/her server, his/her rules; their server, their rules. They can block servers or choose a small number of servers they want to federate with; they can block channels; it's their call, their freedom. But calling and shaming others—who are in other servers—to conform or force to your own ideals, is crossing the line.
I'm sorry, I don't like it whenever I see some people dictating to admins of other servers/intances/hubs/pods/nodes and their users what they can and can not do.
PS To prevent someone twisting my words or cherry-picking or misquoting me, I am reiterating, if it's something that should be hidden (like adult/R18 materials) you can use tags to trigger filters; or move to a server/pod/hub/instance/node that is federated with a few only and caters to whatever "should be hidden" material it is about.
Oh, and feel free to block my channel if the truth hurts you; you'll be doing me a favor. 😋