They're not unhappy about their data being intentionally republishable. C'mon. On the contrary, they are saying that when the product gets successful, they will pull the rug. Like facebook did before, and like twitter did with the API and now again.
It's the same effect as any platform that tries "free speech" invariably becomes a nazi echo chamber, because the only people who WANT to use the less popular system are those that CAN'T or REALLY REALLY REALLY cling to their ideology.
So indeed, most people (normies) will naturally flow towards larger and more mainstream instances. It's already tilting in that direction and actively encouraged in the signup process.
As these instances grow, they will simply have more disagreeable posts (from the perspective of the ideological instances) leading to even more defederation, hence the split will become ever harder over time.