[Cyberdog]

This more or less has already happened, though there are more than two "groups" depending on how you define such things. Broadly speaking, there are free speech instances which allow edgelord teens to come in and N-word their hearts out (as well as do more mundane things like question the mainstream narrative on elections, the pandemic, and, yes, this Pelosi story) so long as they don't do anything actually illegal, and there are more regulated instances where "hate speech" is explicitly forbidden. As the instances in the latter group don't like the practices of the former group, the former insulates from the latter by defederating those instances, meaning that insances in both the former and the latter can generally only federate with each other. (Then there are the pro-MAP/CP/lolicon instances, which are generally defederated by both of the previous groups and also can largely only federate with each other.)

Whether you think this is a good thing is up to you, but it does seem that both groups of people on either side of the Great Divide get what they want from the system, so I don't really see the harm in it.