I agree with the other commenters who say that the issue is primarily that the Lemmyverse is too small for the grifters to bother influencing, but I also think federation (and the non-profit nature) plays into this.

A site like Reddit generally does not ban members just for being Conservative and expressing relatively mainstream right-wing beliefs. They have to present at least a veneer of "free speech" except in the case of hate speech and violence. In addition, they don't want to drive away Conservative users, because that's where their money comes from.

To a small Lemmy instance, these motives don't come into play. More users actually costs the admins more money. And while they generally don't ban users willy-nilly, they feel they have a right to ban people just for being right-wing dicks.

Ultimately right-wing ideology cannot survive in a space like this except in explicitly right-leaning instances; which will be subject to the "Nazi Bar" effect until those instances are defederated from the rest of the Lemmyverse.