Mastodon is not niche. Mastodon is a diverse community of nerds and low tech people, artistic brains and analytical brains, white collar workers and blue collar workers. A substantial portion of Mastodon is from Reddit refugees. Reddit is no more niche than Facebook.

The greater Mastodon venue who that poll reached lacks right wing conservatives, who tend to stay in their bubble of extremist networks. That does not make Mastodon “niche”. Running the same survey on a right wing Mastodon node might be interesting, but we can see from the linked poll that political affiliation is generally orthoganol on this issue.