Requires pretty big buy in. Having to run your own instance is a big ask for most people and since whole idea of Mastodon revolves around the operator censoring discourse on their instance you pretty much have to run your own instance unless you want some random Joe deciding what you see and can post about.
Idea here is good, but I cringe at the main selling point being able to censor topics you don't like.
There are. Mastodon's problem (and/or best feature depending on how you look at it) is that it's pretty prevalent about their blocklists. So the most commonly federated and advertised places tend to be more liberal leaning. I don't keep close track of the community, but this is one blocklist that I just googled https://toot.cafe/about/more#blocked-instances
Aside from the obvious terrible shit the list itself looks kinda passive aggressive in tone
The more conservative demographic also has other more...professional(?) options in the form of Truth Social and Gab. At one point Gab was federated but got blocked into oblivion to the point where they decided to go standalone https://reclaimthenet.org/mastodon-blocks-gab/
It seems to me that for some it is enough that you don't block what they block or even ask someone why someone is blocked and voila, you are blocked too.
I absolutely see the value of blocking and there are things I am happy to block, but I have never seen the need to block anyone based on who they don't block.
It is kind of the outrage over Elon Musk buying Twitter: people are outraged not because they are blocked or prohibited from blocking others but because someone else might not be blocked by default.
Assuming by 'conservative' and 'libertarian' you mean 'right wing'... [sorry. But American political labels are confusing from a European viewpoint] ... that's because the fediverse is just as censorious as all the social media it seeks to replace.
Last time I looked into this fediverse stuff, the biggest 'Mastodon' instance by number of users was affiliated to gab.com. But good luck finding that, if you check out any of the directories of instances, as they [the rest of the fediverse] pretty much all decided to blacklist the Gab instance and block users on those Gab instances from being able to interact with any of the other instances. I think, in the end Gab went off, forked Mastodon and rolled their own version.
BTW --I'm not a right-winger or supporter of Gab in any way. I have no interest whatsoever in US politics. But I did note the irony that; the first thing the kind of people who protest most loudly that we need open alternatives to Twitter et al did, when they got their hands on the control levers of their own tiny Twitter clones, was to start banning people and silencing viewpoints they disapproved of.
Most Conservatives have instead gone to platforms that actively advertise for their specific niche. Especially places like Gab and Parlar. Although Telegram has been a very popular gathering place as well.
Libertarian Tech folks are actually a small minority in the grand scheme of things, and any I know are definitely in favor of Mastadon. But non-tech folks have a much harder time understanding and building out the platform.