@Moon Yeah the level of research ethics varies a lot with disciplines and countries, which is also why we shouldn't just rely on that. Making it easier to respect wishes will go a long way though.
As for research on the fediverse I agree that it will be even more skewed demographically than Twitter if you want to make claims about 'people online' or whatever. However I think there are specific areas of research that the fediverse allows for. On interoperability and governance for example as there is a lot of corporate misinformation on that front. In European commission hearings Facebook for example claimed that e2ee interoperable chat was not technically possible, as a way to soften the interoperability requirements for their chat offerings..